The Science Behind the Art™

Articles

Author: pcarter

Border Carnations

 

Carnations (Dianthus caryophyllus and hybrids), with their ragged, “pinked” edges, lovely colors, and long vase life, are staples of the cut flower trade.  They also have a lengthy and celebrated history in gardens, going in and out of fashion many times over the centuries.  The plants are having a renaissance right now, as flower lovers have come to appreciate their tried and true virtues.

About Dianthus

Carnations make lovely garden flowers, especially in early summer.

The dianthus family is large, with over 300 species, and contains carnations of all sizes, not to mention sweet Williams and the short-statured plants known in this country as “pinks”.  In Europe, especially in Great Britain, the term “pinks” is used more generally to include just about all dianthus.  Given the amount of interbreeding among species over the years, this may be the best informal way to categorize the whole group.

The flowers that you buy in bunches at the local florist or supermarket are generally referred to as “florists’ carnations”.  They are specific varieties grown under greenhouse or controlled field conditions and sold in bulk to the floral trade.  Cultivars that grow outdoors in home gardens are categorized as “border” or “garden” carnations.  Between the two categories, the world of beautiful carnations is wide.

Garden Carnations

Carnations are available in lots of cheerful colors and most are fragrant.

Border or garden carnations are generally short-lived perennials, hardy in USDA Zones 6 through 10.  The stems can grow as tall as 3 feet, though many varieties, especially those developed in the last few decades, are considerably shorter.  The stems are erect but tend to arch.  Depending on height, some garden types may need staking or other means of corralling.  The blue-green to gray-green leaves are long, narrow and attractive in their own right.

The singular look of the flowers is a combination of the distinctive ragged or ruffled edges, and the opulent, semi-double or double petal array of each flower.  Most bear a characteristic spicy scent reminiscent of cloves, sometimes with other sweet fragrance notes mixed in.  Available colors range from purest white to near-black, with bi-colored or even tri-colored varieties available from specialty merchants.  While there are no true blue carnations (unless you put a cut stem in a container of water mixed with blue dye), the color and pattern ranges are still impressive.

Modern Garden Carnations

The ‘I Heart You’ Carnations has bright pink blooms that age to near-white.

Modern large-flowered garden carnations are the result of hybridization of several different species.  English author and gardener Vita Sackville West wrote admiringly about the Chabaud carnations, developed by a French hybridizer in the eighteen seventies.  Some Chabaud types, like the pink-flowered ‘La France’ and ‘Benigna’, with white petals laced with red, are still in commerce today.  Another antique variety, ‘Mrs. Sinkins’, combines shorter stature—about 12 inches tall—with big white flowers.

Modern varieties tend to be more compact than some older ones and come in an array of arresting colors and color combinations.  As with many commercial hybrid plants, they are often marketed in named series protected by trademarks.  Each series shares common features, like short stature and unusual coloration. Selecta One’s 2020 Dianthus introduction, ‘I♥U’ is a singular beauty with a compact habit and fluffy flowers that are rose-pink when they first open and age to near white.  Scent First™ ‘Tickled Pink’ bears bright cerise flowers on 10-inch stems. ‘Horatio’, a hybrid splashed with dark red and white, grows to 12 inches.  Little Sunflor™ ‘Amber’, at six to eight inches, is shorter still, with bright yellow petals.  Flow® ‘Grace Bay’ is creamy yellow with narrow red edges, and dimensions similar to those of ‘Amber’.  Super Trouper™ ‘Orange’ may be closer to peach than tangerine, but its unusual coloration stands out.

Growing Carnations

Carnations are some of the best cut flowers you can grow if you choose long-stemmed varieties.

Like other members of the dianthus family, carnations are relatively easy to grow if you give them full sun and well-drained soil on the alkaline side of the pH spectrum.  If you have acid soil, it may be best to install your carnations in medium to large containers or add lime to your garden soil according to package directions.  Gardeners with heavy clay can amend the soil with organic material like Fafard® Premium Natural and Organic Compost.

Humans may love carnations, but garden varmints, like rabbits and deer, generally do not.  If you have cats who roam the garden and are prone to sampling plants, take care, as the flowers can be irritating to feline mouths and stomachs.

At different times and places, carnations have been known by evocative names like “sops-in-wine,” “gillyflowers” and clove pinks.  Whatever you call them, they add both beauty and drama to the summer landscape.

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline “garden supervisors” live in northern New Jersey.

Sustainable Gifts for Gardeners

 

The holiday season is the best and worst of times for gardeners’ friends and relatives.  The list of potential gifts is large, but choosing presents that the gardener actually wants or needs can be daunting.  One way to get a handle on the situation is to think about sustainability.  Most people who dig in the dirt—whether that “dirt” is garden beds, window boxes or indoor containers—are looking for sustainability.  Gardening is about working with the environment, not against it, so sustainable gifts are a good choice all the way around.

Small Surprises

Some people call these neat little gifts “stocking stuffers”, but even if you have no stockings, they are thoughtful remembrances.  Garden twine comes in handy in so many situations that it is practically indispensable.  Classicists have long turned to Nutscene Green Twist, which is made of biodegradable jute in a green shade that blends with leaves and stems, but any twine made of jute or hemp will come in handy.  Another small delight is lip balm, preferably made from beeswax.  There is nothing like it when you are putting in those last bulbs on cold, dark, December afternoons.  If you know your friend’s or relation’s preferences in hand lotion, a small jar or tube of that will take care of chapped hands as well.

Protecting the Protector

If you have a rough idea of the gardener’s hand size, a good, sturdy pair of cotton gloves can come in handy.  Likewise with warm socks in natural fabrics.  If you are privy to the individual’s likes, dislikes, and existing closet contents, a raffia or cotton garden hat or visor, may be a good investment.  Look for a generous brim and adjustable size.  Some hats are also foldable or packable, making them an especially good gift.

Tools

Good tools are like gold, and some people are picky about them. It pays to know what tools your friend or relative already has in the garden basket.  A garden knife, sometimes known as a Japanese hori knife, functions as a knife, trowel, and weeder all in one.  For sustainability, invest in a knife with a wooden handle, stainless steel blade and a convenient leather sheath that can attach to a belt.

One of the most indispensable weapons in my garden arsenal is an old-fashioned digging fork, which is smaller than a pitchfork, and about the same size as the average garden spade.  A sturdy wood and stainless fork does a multitude of heavy tasks, including mulching, soil loosening, and turning compost, and generally lasts for years.  If you are planting bulbs in a congested garden area, a fork will get the earth loosened with minimal disruption to neighboring plants or older bulbs that you may have forgotten about.  For new gardeners, a matching fork and spade set, is an exceptionally thoughtful gift.

Building Better Soil

Organic compost is wonderful for adding nutrients to soil, lightening heavy clay, or helping sandy soils retain moisture.  Plants love it.  Many vendors sell small, ceramic countertop units that will hold kitchen scraps until they can be deposited in an outdoor compost pile or composter. These are especially good for people in cold weather climates who may want to skip a trip to the compost pile when the snow is piled high.

A big bag of organic mulch may not make much of an impression under a Christmas tree, but a compact brick of coir-based potting mix, seed starting mix or compost makes a neater package that can be conveniently stored until it is needed.  All the gardener has to do is add water, and the brick’s contents expand into a usable medium.  Gardeners who do indoor seed-starting may appreciate a pack or two of coir seed-starting disks, a sustainable replacement for peat-based disks.

Hard to Buy For Gardeners

Suppose your gardening friend or relative already has an ample supply of tools, hats and soil amendments?  What then?  Most horticulture-minded people have a favorite nursery or garden center.  An online gift card is thoughtful and sustainable and allows your loved one to choose something suitable.  A subscription to the online edition of a gardening magazine (or the print edition for those who prefer it), provides a year’s worth of inspiration, usually at a relatively low price.  Membership in non-profits like the American Horticultural Society, Great Britain’s Royal Horticultural Society, or the Southern Garden History Society provide all kinds of benefits, in addition to publications, conferences and, sometimes, discounts at botanical institutions.

Classic garden books are another sure winner.  The internet is full of features on how to plant and design gardens.  Good garden literature delves into the “why” of doing so.  Classic works by authors like Russell Page, Beth Chatto, Christopher Lloyd or Henry Mitchell never go out of style.  Page Dickey has written about aging—and making gardens—gracefully.  Stephen Orr’s The New American Herbal is a must for herb lovers, gardeners and cooks.

For something really personal, try giving your time to help with heavy, but necessary garden chores like spreading mulch, digging a new bed, or bringing large container plants inside for the winter.  You will be investing in both gardens and friendship.

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants, a healthy stand of Hollyhocks, as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline Saki. “garden supervisor” live in northern New Jersey.

Native Shrubs for Hummingsbirds

 

Every hummingbird garden could use a native shrub or two (or more!). Here are seven of the best hummingbird-pollinated shrubs from central and eastern North America.

 

New Jersey tea (Ceanothus americanus)

How the Garden State was credited with this wide-ranging U.S. native is anyone’s guess. In any case, New Jersey should be flattered. Give Ceanothus americanus a sunny site and well-drained soil, and it will give you a knockout display of fragrant conical white flower clusters from late spring into summer. At around 3 feet tall and wide, it is a great fit for mixed borders, entry plantings, and of course wildflower gardens. Western U.S. gardeners can choose from Ceanothus native to their region, including the wealth of species and hybrids known collectively as California lilacs. One of the great joys of Pacific Coast gardening, their flowers open over a long season and come in several colors including white, blue, and pink.

Buttonbush (Cephalanthus occidentalis)

Occurring in wetlands over much of the North American continent, buttonbush does just fine in any moisture-retentive garden soil – although it may need occasional watering during prolonged droughts. If your soil is on the sandy side, amend it with Fafard Premium Natural & Organic Compost. Where happy, buttonbush produces numerous fuzzy spheres of white flowers in early summer on rounded 6- to 10-foot plants. If that is too big, you can give plants a severe pruning in early spring (plants will flower on the resulting new stems), or use a compact selection such as ‘Sugar Shack’. When not in flower, buttonbush features large, handsome, glossy rich-green leaves, which turn muted yellow and pink shades in fall.

Summersweet (Clethra alnifolia)

Another moisture-loving shrub, summersweet forms thicketing clumps of upright 4- to 6-foot stems that terminate in bottlebrush columns of small white or pink flowers in summer. The flowers carry a pleasant, somewhat root-beer-like fragrance. Also of ornamental interest are the shiny, oval, mid-green leaves, which turn a butter-yellow in fall. Found in damp semi-shaded habitats across its Nova Scotia to Texas natural range, summersweet will also do fine in full sun if the soil is consistently moist. Red spider mites and other pests and diseases can be a problem in overly dry sites. Available varieties include deep pink flowered ‘Ruby Spice’, and 3-foot-tall, white-flowered ‘Sixteen Candles’.

Southeastern gardeners have another outstanding native Clethra for the garden, cinnamon bark pepperbush (Clethra auminata). Its steepled white summer blooms occur on 10- to 15-foot plants with attractive peeling cinnamon-brown bark. This large shrub or small tree is hardy as far north as USDA Zone 6.

Bush honeysuckle (Diervilla spp.)

If you are looking for native shrubs for dryish shade, you will want to consider these handsome suckering cliff dwellers from wooded uplands of eastern and central North America. Close relatives of honeysuckles (Lonicera spp.), they bear yellow funnel-shaped flowers in summer on arching, 2- to 4-foot-tall stems. Diervilla lonicera is native to the northeastern and north-central U.S. and northward into Canada, whereas Diervilla sessilifolia and the much rarer Diervilla rivularis have a more southerly range. All bush honeysuckles have sunset-toned fall foliage, with some selections and hybrids such as ‘Copper’ producing brightly hued new leaves.

Chokecherry  (Prunus virginiana)

A cherry species that is as American as cherry pie, this small tree is found in all of the lower 48 states, as well as in most of lower Canada. Tolerant of heat, bitter cold, drought, salt spray, and other environmental stresses, it makes an ideal street tree for most soil types. Among the best and undoubtedly the most widely planted varieties is ‘Canada Red’, with leaves that open green but mature to maroon in early summer. The white flowers spring flowers and purple summer fruit are ornamentally inconsequential.

Fragrant azaleas (Rhododendron spp.)

All members of the rhododendron tribe attract hummers, but among the best for native gardens are two spicy-flowered species – roseshell azalea (Rhododendron prinophyllum) and swamp azalea (Rhododendron viscosum). The funnel-shaped blooms of these two eastern and central North American natives carry a far-reaching clove-like scent, which may not attract hummingbirds but certainly draws in humans. Roseshell azalea produces pink flowers in mid-spring, weeks before the white blooms of swamp azalea (with some swamp azaleas such as ‘Pink and Sweet’ producing pink flowers). They do best with moist to average soil and a bit of shade.

Highbush blueberry (Vaccinium corymbosum)

Who doesn’t love our most familiar eastern and central North American species of blueberry? Hummingbirds are certainly in on the love, paying nectar-sipping visits to the white urn-shaped spring flowers of this large shrub. Of course, among the results of these pollinating forays are the tasty blue early-summer fruits. Other Vaccinium species also attract hummers, including the widely cultivated Southeast native rabbiteye blueberry (Vaccinium virgatum), and the Pacific Coast native California huckleberry (Vaccinium ovatum).

 

 

 

About Russell Stafford

Hortiholic and plant evangelist, Russell Stafford, transplanted his first perennial at age 7 and thereby began a lifelong plant addiction. He is the founder and custodian of Odyssey Bulbs (and Odyssey Perennials), an online nursery specializing in cool and uncommon plants. Russell also works as a horticultural consultant, freelance writer (Horticulture and The American Gardener magazines), and garden editor. He formerly served as Curator and Head of Horticulture at Fernwood Botanic Garden in Niles, Michigan and as the Horticultural Program Coordinator at the Center for Plant Conservation, then located at the Arnold Arboretum in Jamaica Plain, Massachusetts. His academic degrees include a masters in forest science from Harvard University.

The Ins & Outs of Holiday Cactus

What is the difference between a Thanksgiving cactus and a Christmas cactus?  Inquiring, plant-loving minds want to know.  Also, are those seasonal bloomers the same as Easter cacti?  Do they all require the same care and culture?  Confusion seems to abound in the world of flowering holiday cacti.  Lots of people have them, but not everyone knows the answers to those pertinent questions.

Holiday Cactus Basics

Let’s start with the obvious.  All holiday cacti are houseplants with segmented, succulent leaves, arching stems, and, in certain seasons, brightly colored flowers at the ends of the stems. They owe their popularity to the fact that they are relatively undemanding plants that can live for years under the right conditions. Thanksgiving and Christmas cacti have the added benefit of producing bright flowers during the dark months.

Thanksgiving and Christmas cacti, sometimes billed as “zygocactus”, are both members of the genus Schlumbergera, named for Frederick Schlumberger, a nineteenth century botanist.  Thanksgiving cactus is a species (Schlumbergera truncata), while Christmas cactus (Schlumbergera x buckleyi) is a hybrid, with the truncata species in its ancestry.  Some of the most popular holiday cacti, including the Christmas cactus (Schlumbergera x buckleyi), are hybrids, which may further complicate identification.

Giving Thanks for Bright Blooms

Thanksgiving cacti hail from tropical Brazilian rainforests where the species grows epiphytically on trees.  The Thanksgiving plants are distinct from other holiday cacti by the fact that their flat, segmented leaves, which end in points, making them appear a bit clawlike.  This trait gave rise to one of the species’ nicknames, “crab cactus”. Another distinguishing feature is the pollen, which is yellow. Container-grown specimens grow from one to two feet tall and can spread up to two feet.  Most selections sold in stores at holiday time are somewhat smaller, but a happy plant will bulk up as the years go by.

Thanksgiving cactus generally bloom in November or December, just in time for the Thanksgiving holiday, with flowers in shades of white, pink, peach, orange or yellow.

Christmas Cactus

Like Thanksgiving cactus, Christmas cactus bears segmented stems, but instead of the “claws” at the ends of the segments, the edges are more rounded—with a slight teardrop-shape.  Christmas cactus also features pink pollen, borne by the stamens within the flowers, which are traditionally reddish-purple.  The plants are roughly the same size and configuration as Thanksgiving cactus, but bloom a bit later, usually from the end of December, through January.  The species name, buckleyi, comes from a nineteenth century English hybridizer, William Buckley.

Hybrids Gone Wild

Plant breeders always latch onto good things, and that is especially true with hybrid Schlumbergeras, which are often simply labeled “holiday cactus”.  Their work has extended the color range, increased flower size and shape, and created hardier plants.  A good example is ‘Aspen’, with broad, white, frilly petals accented by pink rings in the flowers’ throats.  ‘Chiba Spot’ is ‘Aspen’s opposite, with extremely slender petals in orange-red.  ‘Limelight Dancer’ blooms in an unusual color–pale yellow with green overtones—and sports contrasting pinkish pistils.  The amount of variety in the Schlumbergera world seems to increase each year.

And What About Easter Cactus?

Easter cactus, while related to the holiday cacti is not a Schlumbergera, but a Rhipsalidopsis, specifically Rhipsalidopsis gaertneri.  It is a little less popular and a little more finicky than either Thanksgiving or Christmas cactus, being quite sensitive to both over and under-watering.  The flattened leaf segments are the same, but are somewhat scalloped.  The flowers are brilliant red, but with shorter tubes than those of the holiday cactus.

Cactus Care

All three holiday cacti like excellent drainage—ideally orchid mix or potting mix lightened with organic matter, like Fafard® Premium Natural and Organic Compost, and perlite.  Indoors the plants thrive best with bright, indirect light.  To stimulate blooming, night temperatures should be between 55 and 65 degrees Fahrenheit.  Water sparingly when the top of the soil feels dry to the touch,  Easter cacti like higher humidity, either through regular misting, a room humidifier or a position atop a tray filled with pebbles and water.

Holiday cacti appreciate an outdoor summer vacation in a lightly shaded spot, as long as that spot doesn’t get swamped in rainstorms.  Bring the plants in when night temperatures start to drop below 55 degrees Fahrenheit and days begin to shorten.  After the outdoor vacation, Thanksgiving cacti will frequently start to show color on the stem tips, a prelude to bud formation and blooming.  Christmas cactus will not be far behind.

With good care, the plants will survive and rebloom for years to come.

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants, a healthy stand of Hollyhocks, as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline Saki. “garden supervisor” live in northern New Jersey.

Cool Summer Blues by Russell Stafford

Midsummer is a hot time in the perennial garden. This is true not only of the weather, but also of the flowers that hold sway at this season. Rudbeckias (featured here last month), sunflowers, coreopsis, heleniums, goldenrods, bee balms, and numerous other large perennials with hot-colored flowers reach their peak from July into September, saturating the garden with their dazzling hues.

Blue-flowered perennials that bloom in summer make a refreshing, cooling contrast to these dominating fiery hues. Their relative rarity has led to near-overuse of several of them including English lavender (Lavandula angustifolia), hybrid sage (Salvia x sylvestris), spiked speedwell (Veronica spp.), and Persian catmint (Nepeta racemosa). The ranks of blue-flowered perennials include quite a few other excellent choices, however.

 

Spark’s and Bicolor monkshoods (Aconitum ‘Spark’s Variety’; Aconitum ‘Bicolor’)

Literally a midsummer standout in full to part sun and rich moist coolish soil, ‘Spark’s Variety’ sends up stately branching clusters of deep violet-blue, helmet-shaped flowers in July and August. The 4- to 5-foot stems sometimes need staking. The variety ‘Bicolor’ owes its name to its two-tone violet-blue and white flowers, borne on 40-inch stems at about the same time as those of ‘Spark’s Variety’.  As with all monkshoods, they do best in areas with relatively moderate summers in USDA Hardiness zones 3 to 9, and suffer in hot humid conditions. Handle monkshood roots and other parts with caution: they contain potent toxins that make them a potential risk, especially in proximity to children, pets, or edible plants.

African lily (Agapanthus spp.)

Some cultivars of these southern African natives are remarkably hardy, wintering in USDA Zone 6 (or even 5) under a thick coarse mulch (such as oak leaves). Among the hardiest are the selections ‘Galaxy Blue’ and ‘Blue Yonder’, which bear rounded clusters of blue trumpet-shaped flowers from early- to mid-summer on upright 3-foot stems. Other hardy cultivars include white-flowered ‘Galaxy White’, as well as a group of blue- and white-flowered variants that go under the collective name ‘Headbourne Hybrids’. The clumps of strap-shaped basal leaves are also ornamental. Hardy species have deciduous foliage, whereas most cold-tender Agapanthus are evergreen, qualifying them as four-season houseplants (or garden subjects, where suitable). Deciduous varieties can be dug and stored bare-root over winter.

Anise hyssop (Agastache spp.)

The eastern U.S. native Agastache foeniculum provides a summer-long display of lavender-blue spikes atop 3- to 4-foot stems. Pollinators of all sorts swarm the flowers.

Its anise-scented and-flavored leaves contribute to the edible garden as well, making a spicy addition to salads and stir-fries. An enthusiastic self-sower, anise hyssop will happily seed itself about the garden, if allowed. Hybrids between anise hyssop and its East Asian relative Agastache rugosa tend to be sterile (no seedlings) and relatively compact; these include ‘Blue Fortune’, ‘Black Adder’, and ‘Blue Boa’. They’re also a bit less hardy than Agastache foeniculum, to USDA Zone 5 rather than 3. All agastaches do best in sunny, well-drained garden niches.

Calamint (Calamintha nepeta)

Hazy swarms of small pale blue or white flowers hover above low mounded clumps from early summer until frost. The headily mint-scented leaves of this sun-loving perennial flavor many traditional dishes in Italy, where the plant is known as nepitella or mentuccia. Calamint also makes for an excellent mojito. It’s ideal for massing in perennial plantings, or for dressing up vegetable and herb gardens. Plants are hardy from zones 4 to 10.

Plumbago (Ceratostigma plumaginoides)

Few ground covers are as colorful as plumbago. Scatterings of deep sky-blue, rounded flowers spangle its spreading, foot-tall stems beginning in summer. Bloom continues into fall, as the foliage turns showy wine-red hues. Happiest in sunny, well-drained sites in hardiness zones 5 to 10, plumbago also accepts a modicum of shade. Shear plants back in late fall or early spring.

Tube-flowered clematis (Clematis heracleifolia)

A total departure from the large-flowered, vining hybrids by which many gardeners know clematis, this large shrubby perennial produces clusters of fragrant, tubular blue blooms in mid- to late summer.  The 3- to 4-foot stems sprawl rather than climb, typically requiring staking. Selections and hybrids of the subspecies davidiana (including the cultivar ‘Wyevale’) are distinguished by their showy, wide-flaring flowers that appear a bit earlier in the season than those of the straight species. Sun to partial shade, good well-drained soil, and relatively mild zone 3 to 9 summers suit all forms of the species best. Plants will be especially happy if you give them a spring mulching of Fafard® Premium Natural & Organic Compost.

Great blue lobelia (Lobelia siphilitica)

Also oxymoronically known as blue cardinal flower, this central and eastern North American native is a close cousin and compatriot of the incandescently red-flowered Lobelia cardinalis. It’s a more adaptable and long-lived garden plant than its scarlet relative, however. Give it a moist to dryish, sunny to partly shaded location and just about any type of soil and it will bring forth its 3-foot candelabra spires of mid-blue flowers in July and August. When not in bloom, it retreats to a low rosette of gently toothed, tongue-shaped leaves. After a year or two, you’re likely to have several more such rosettes and spires, thanks to self-sowing.

Russian sage (Perovskia spp.)

The aromatic grayish-green foliage and slender spires of violet-blue flowers of this shrubby perennial give it something of the feel of an oversized lavender. The individual leaves are broader and more toothed than those of lavender, however, and the flowers come somewhat later in the season, from July to October. Perovskia atriplicifolia – the prototypical Russian sage – ascends (to more than 4 feet tall, but numerous more compact hybrids and varieties are available. These include ‘Blue Spritzer’, which flowers prolifically on 30-inch stems with oval, untoothed leaves; ‘Little Lace’, with relatively deep-hued blooms and finely divided leaves on 32-inch plants; and ‘Denim ’n Lace’, an especially showy 32-inch-tall selection that features deeply toothed leaves and 24-inch spikes of relatively dark-hued purple flowers. Russian sage thrives in sun and lean soil. Plants should be cut back to a few inches from the ground in spring, before leaf-break.

Balloon flower (Platycodon grandiflorus)

Inflated flower buds that do indeed resemble miniature balloons open to cupped 5-pointed flowers in early summer. Typically purple-blue, they also come in white, pink, or a variegated mix of these colors. The buds of a few varieties such as ‘Komachi’ do not open, remaining as balloons. Flowering occurs atop clustered upright 30-inch stalks that arise from tuber-like roots relatively late in spring. Dwarf varieties such as 10-inch-tall ‘Apoyama’ are also available. Balloon flowers make good subjects for well-drained, sunny to partly shaded niches in zones 3 to 10.

Downy skullcap (Scutellaria incana)

This native of dry woodlands and other challenging habitats in the central and eastern U.S. is undoubtedly one of the best and most overlooked blue-flowered perennials for sunny to partly shaded sites in those regions and beyond (zones 3 to 9). Branching clusters of tubular, two-lipped, mid-blue flowers ornament the garden for many weeks starting in early summer, attracting bumblebees and hummingbirds. They occur on erect, 3-foot-tall plants, with self-sowing often occurring.

 

 

 

About Russell Stafford

Hortiholic and plant evangelist, Russell Stafford, transplanted his first perennial at age 7 and thereby began a lifelong plant addiction. He is the founder and custodian of Odyssey Bulbs (and Odyssey Perennials), an online nursery specializing in cool and uncommon plants. Russell also works as a horticultural consultant, freelance writer (Horticulture and The American Gardener magazines), and garden editor. He formerly served as Curator and Head of Horticulture at Fernwood Botanic Garden in Niles, Michigan and as the Horticultural Program Coordinator at the Center for Plant Conservation, then located at the Arnold Arboretum in Jamaica Plain, Massachusetts. His academic degrees include a masters in forest science from Harvard University.

Caryopteris by Elisabeth Ginsburg

The first time I heard the word “bluebeard”, I thought about the old French fairy tale about a murderous nobleman and his unfortunate wives.  A little research proved that caryopteris, the shrub that goes by that nickname, is neither French, nor murderous.  In fact, bluebeard, sometimes also known as “blue mist shrub” or ‘blue spirea”, is downright joyful and brings color to the late summer landscape.

Blue, even when it tends to blue-purple is a wonderful color in the garden, and it is especially welcome in late summer and early fall—generally just ahead of the mums and asters– when blue mist shrubs burst into bloom.

The most common forms of blue mist shrub are varieties of Caryopteris x clandonensis, a hybrid of two caryopteris species, Caryopteris incana and Caropteris mongholica.  The happy result of the hybridizing process is deciduous shrubs that grow two to three feet tall, with green to gray-green, oval-shaped leaves that taper to elegant points.  The leaves, which release a pleasant fragrance when brushed, give away the fact that Caryopteris is a member of the enormous mint or Labiateae family.

The “blue mist” that give Caryopteris species, hybrids and varieties their common name, is made up of clusters of small blue flowers that appear at the ends of the arching stems and in the leaf axils where stems and leaves meet.  The “beard” that gave rise to the common name “bluebeard” is actually a small tuft at the base of each tiny petal. Butterflies and other pollinators probably don’t care about the beards, but they do covet the abundant nectar in the tubular blooms. Perhaps best of all, the plants flower on the current year’s growth, so early spring freezes will not prevent later summer flowering.

Gardeners are spoiled for choice when it comes to caryopteris.  The classic variety is ‘Longwood Blue’, a hybrid developed at Longwood Gardens in Pennsylvania.  Sky blue flowers ornament a plant that grows to be about three feet tall and at least as wide.  A little smaller, with darker, richer-colored flowers, ‘Beyond Midnight’ is another x clandonensis hybrid that reaches about 2.5 feet tall and wide.  It might work well in large containers.

To light things up further, ‘Sunshine Blue’ sports golden-green foliage to go along with its medium blue flower clusters.  It grows to about the same dimensions as ‘Longwood Blue’.

Since blue mist shrubs flower only once per growing season, variegated foliage helps sustain interest before and after bloom time.  ‘White Surprise’ is a clandonensis hybrid with green petals edged in white.  ‘Snow Fairy’, a variety of the Himalayan species Caryopteris divericata, also sports white-edged leaves.

But what about the vogue for pink in fashion and flowers?  Blue mist shrubs are also available with pink “mist” (though they retain the “blue mist” name).  ‘Beyond Pink’d’ is a variety of Caryopteris incana, one of the parents of the clandonensis hybrids.  It boasts the same aromatic foliage and flower panicles as its blue-flowered relatives, but the bloom clusters are medium pink.  Its pollinator-attracting capabilities are the same as those of other caryopteris.

With its moderate size and colorful late summer flowers, blue mist shrub makes a good addition to beds, borders or even container gardens, provided the containers are large enough.  It also has the potential to make an excellent deciduous hedge, or shine as a single specimen.  The clandonensis hybrids are generally hardy in USDA plant hardness zones five through nine; ‘Beyond Pink’d’ and other incanas are a little less cold tolerant.  They and even some of the caryopteris hybrids may die back to the ground during cold winters, but will sprout up in the spring with no ill effects.

What conditions make for a happy caryoperis?  Sunlight is important, and the shrubs need about the same light exposure as roses or tomatoes—at least six hours per day.  Like humans, blue mist shrubs dislike wet feet, so amend heavy soil with a product like Fafard Premium Natural and Organic Compost.  Mulch the shrubs in doughnut fashion, with the mulch surrounding, but not touching the base of the plants.  Water regularly while the new shrub establishes its roots.

If you crave caryopteris when you see a neighbor’s shrub flowering, take heart.  The plants can be purchased and planted in early fall.  If your pocketbook is subject to other demands right now, rest assured that “blue mist” can still blow your way next spring.

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants, a healthy stand of Hollyhocks, as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline Saki. “garden supervisor” live in northern New Jersey.

Late Summering Flowering Trees By Elisabeth Ginsburg

In spring the whole world seems to bloom, with a wide array of flowering trees and shrubs joining the parade of daffodils, tulips and hyacinths.  The pace of mid to late summer is slower, which gives gardeners and flower lovers more time to appreciate the changing show.

If you are thinking about including a summer-flowering tree in your landscape, the choices are varied, from the cascading fringe of sourwood, to the camellia-like blossoms of the native Franklinia tree.  While not so numerous as the spring-flowering trees, summer bloomers come in all sizes and configurations.   If you happen to have an arboretum, you can have them all.  For the rest of us, the hardest part is choosing only one.

The Sweetness of Sourwood

Known for its (allegedly) bitter leaves and decidedly sweet fragrance, sourwood (Oxydendrum arboretum) is a deciduous native of the southeastern United States.   Related to members of the heath and heather or Ericaceae plant family, the species is also known as “Sorrel tree”, or, more sweetly, “lily-of-the-valley tree”.  In cultivation sourwoods grow to about 25 to 30 feet tall and about 20 feet wide, with shining, oval-shaped leaves that are green in summer and brilliant red or red-purple in the fall.  In very late June or July, sourwood trees are completely clothed in drooping flower panicles made up of tiny, individual chalice or urn-shaped blooms that last up to a month, spilling out over the leaves and giving the trees a singular appearance.

Well-drained soil and full sun to light shade make for happy sourwoods, and the trees are hardy in USDA Zones 5 through 9.  Lovers of variegated leaves may be interested in Oxydendrum arboretum ‘Albomarginatum’, which boasts white leaf edges.

Franklin’s Tree

Perhaps fittingly for something discovered during America’s colonial period, the Franklinia tree (Franklinia alatamaha) is a member of the tea family.  Other notable members include camellias, so it is no coincidence that the beautiful Franklinia flowers, which appear in late July, August and sometimes into September, are camellia-like.

Franklinias, hardy in USDA Zones 5 through 8, are especially appropriate for smaller gardens, growing between 10 and 20 feet tall and up to 15 feet wide, with spreading branches.  The glossy leaves are narrowly tapered ovals with soft undersides.  In the fall those leaves turn red to purple.

The tree’s greatest glory, however, may be the fragrant flowers, which are white, with five petals apiece surrounding a sumptuous boss of golden stamens.

Franklinias like well-drained soil on the acidic side of the ph scale.  To get the best from the plant add organic material, like Fafard Garden Manure Blend to the soil when filling the planting hole.

Discovered in the wilds of Georgia in 1770, Franklinia disappeared from its habitat sometime afterwards.  Thanks to colonial plantsman John Bartram, who collected the seeds and named the newly discovered species after his friend, Benjamin Franklin, last summer flower lovers can enjoy Franklinia today.

Great Crape

Crape myrtle (Lagerstroemia sp.) is a small tree that generally tops out at 15 to 25 feet.  The many available varieties shine with brilliant summer flower panicles or branching clusters composed of scores of individual six-petaled blooms in shades including white, a range of pinks and roses, dark red and lavender.  Crape myrtle flowers are spellbinding when they bloom, but the plants pull their weight in all four seasons. The leaves, which are oblong and appear in groups of three, tend to be smooth and glossy green, coloring up in the fall in shades of red, orange and yellow. Most varieties also have smooth grayish bark that exfoliates or peels off to reveal underbark that may be brown, gray or even pinkish.  The effect is like elegant camouflage, and it makes crape myrtles stand out during the cold months when leaves and flowers are a thing of the past.

The most common crape myrtles in commerce are varieties or hybrids of Lagerstroemia indica, which is native to parts of Asia, and the list of colors and sizes is long.

Crape myrtles like the same conditions as roses—full sun for at least six hours per day.  If your chosen site receives a little less light, the tree or shrub may still thrive but will likely produce fewer flowers.  Plant in well-drained soil enriched with organic material and mulch thoroughly.

If crape myrtle can be said to have a downside, it may be zone hardiness.  Older varieties are probably only hardy from USDA Zone 6 or 7 through Zone 9.  Newer cultivars have been bred for greater cold tolerance, but it pays to check plant tags before purchasing.

Perfect Pagodas

A tall, upright, deciduous tree with spectacular late summer flowers, the Japanese pagoda tree (Sophora japonica) is not native to Japan, but hails from China.  Reaching 50 to 75 feet tall, with a nearly equal spread, it is majestic, perfect as a specimen or even street tree.  Pagoda trees sport medium green leaves that are pinnate, with each five to ten inch “leaf” composed of a number of short leaflets that sprout from a single stem.  In July or August, those leaves are complemented by elongated clusters of pea-like white flowers that are lightly fragrant and attract pollinators.  After the petals drop, the yellow-green seed pods appear, hanging from the trees like strings of beads.  Eventually those pods turn brown and split.

Japanese pagoda trees prefer full sun to part shade, and well-drained loamy soil.  Once established they are tolerant to environmental stressors, including air pollution.  The most popular variety is ‘Regent’, which grows more quickly than the species. Pagoda trees are hardy in USDA Zones 6 through 9.

And For Colder Climates…

If you live in USDA Zones 3 or 4, where winters are colder, you can still grow trees with late summer flowers. Panicle hydrangea (Hydrangea paniculata), can be grown either as a shrub, or, as is often the case, trained (either by a nursery or by the gardener) to grow as a small tree.  In tree form, it can grow up to 15 feet tall with a wide crown.  From July through September the hydrangea will bloom, producing fat, conical flower panicles composed of scores of individual white blossoms that eventually age to pink and then ten.  Hardy in USDA Zones 3 through 8, panicle hydrangeas are also tolerant of air pollution, but dislike drought.  Plant in full sun and provide supplemental water during hot, dry weather.

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants, a healthy stand of Hollyhocks, as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline Saki. “garden supervisor” live in northern New Jersey.

Great Groundcovers by Elisabeth Ginsburg

Perennial groundcovers are the workhorses of the garden—insulating the soil, smothering weeds and beautifying the landscape all at once.  Given a little care and water while they get established, most groundcovers with grow happily with minimal attention from the gardener.  All provide a green carpet and some color up in the fall. Many have the added attraction of seasonal flowers.

A great groundcover forms a thick mat and spreads horizontally. As with any plant, finding a successful groundcover is a matter of “right plant, right place.”  Adding a quality soil amendment, like Fafard® Premium Natural and Organic Compost Blend, at planting time will encourage any low-growing “green mulch” specimen to thrive where it is planted.

The world of ground covers is large, with an array of choices for every site, even if your landscape contains that bane of the gardener’s existence—dry shade.  The following are a few of the best.

Gracious Geraniums

At about 12 inches tall when flowering, big-root geranium (Geranium macrorrhizum) is a stellar groundcover with deeply dissected medium green leaves that smell of apples.  In spring, just after the daffodils and tulips have finished their show, the leaves, are ornamented by five-petaled pink flowers.  When the petals drop, decorative pinkish seedheads appear, with a shape that brings to mind to the plant’s common name, “cranesbill”.

Flourishing in sun or light shade, big-root geraniums spread freely, but are not invasive. In the fall, the foliage turns a festive shade of red.

Geranium x cantabrigiense is a naturally occurring hybrid of big-root geranium and another species, Geranium dalmaticum, with a ground-covering habit.  The leaves are dissected, but are smaller, more rounded and daintier than those of its relative.  Shell-pink flowers accent the popular ‘Biokovo’ variety, appearing in the spring, with leaves that may redden in the fall.

Scents of Thyme

Prostrate or creeping thyme (Thymus) plants make agreeable, often fragrant groundcovers in sunny spots, and are semi-evergreen in cold winter climates. In addition to tiny green or gray-green leaves, many varieties boast small, colorful flowers.  Groundcover thymes are not generally used in cooking, unlike the closely related culinary thyme (Thymus vulgaris).  Some gardeners use prostrate thyme plants in beds and borders, while others position them between stepping stones or on lightly traveled paths.  Flowers may be white, pink or purple-pink, depending on species and variety, with most appearing in early summer.  Among the most popular species are Thymus serpyllum or wild thyme; Thymus praecox; Thymus pseudolanguinosus, commonly known as “woolly thyme”, with softly hairy foliage; and Thymus herba-barona, or “caraway thyme”, which bears caraway-scented leaves that can be used in cooking.

All thymes like well drained soil and, once established, are drought-tolerant.

Hosta Minis

Hostas of all sizes and descriptions are loved for their shade tolerance, beauty, tenacity and ease of care.  Small hostas also make great low groundcovers.  At four to eight inches tall (with taller flower spikes), minis are available in a variety of colors and forms.  The classic ‘Blue Mouse Ears’ features rounded, blue-green leaves, while its sport (spontaneous genetic mutation), ‘Mighty Mouse’ has the same foliage edged in cream.  Light up dark places with ‘Munchkin Fire’, with pointed golden green leaves. Little ‘Lemon Zinger’ also bears pointed leaves with wavy edges and darker green leaf margins.

Happy hostas will multiply quickly into ground-covering clumps that can be easily divided in spring.  The minis are as tough as their larger relatives and do well under trees and in other difficult situations.  Provide consistent moisture during dry periods.

Sweets for the Shade

Another shade loving groundcover with great leaves is sweet woodruff (Gallium odoratum), sometimes called “sweet-scented bedstraw”.  Each dark green leaf is lance-shaped, but the leaves are grouped in rounded, seven-leaf whorls that swirl about eight inches above the soil.  In mid- spring, small clusters of four-petaled white flowers appear.  Both flowers and leaves are fragrant, and can be dried and used in potpourri or sachets. Sweet woodruff spreads handily—sometimes a bit too handily—in its preferred moist, shaded environment, but escapee plants can be hand pulled or mowed easily.  It will grow successfully under black walnut trees, a challenging location for many plants.

Bugleweed Trumpets

With its ground-hugging scallop-shaped leaves and bright blue spring flower spikes, ajuga (Ajuga reptans) attracts attention.  In the species form, the leaves are shiny and dark green, but plant hybridizers have been busy creating varieties with more colorful foliage.  ‘Black Scallop’, for example features darkest purple to black foliage, while ‘Burgundy Glow’ is variegated in cream, sometimes with rosy highlights.  ‘Bronze Beauty’s’ leaves are bronze-red.  All feature similar spikes of tiny blue flowers that attract spring pollinators.  For something familiar, but just a bit different, vendors offer ‘Pink Lightening’, with pink-purple flower spikes.

Ajuga is great for covering areas that have varying mixtures of sun and shade, and prefers consistently moist soil.

If you are covering a large area with any groundcover, start with small “plug” plants and space according to directions on the tags.  Mulch around the new arrivals and water regularly.  Eventually your little plants will spread to meet each other and take over the mulching duties on their own.

 

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants, a healthy stand of Hollyhocks, as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline Saki. “garden supervisor” live in northern New Jersey.

Rudbeckias

Rudbeckias are as American as the Fourth of July. All 20-something species of this sunny-flowered genus call North America home, with most occurring in at least part of the U.S. A familiar sight in meadows, prairies, and gardens, they are commonly known as black-eyed susans or coneflowers – names that allude to the dark-hued central disk that typifies their blossoms. The petals that radiate from this “cone” are usually a bracing bright yellow. The flowers typically continue for many weeks beginning in June or July, starring in the summer (and fall) border. If you want perennials and annuals with a cheerful disposition and prolific summer-long flowers, rudbeckias top the list. For even more prolific bloom, give them a spring topdressing of Fafard® Garden Manure Blend.

They are also easy keepers. Most Rudbeckia (including the following) accept a wide range of soil types, tolerate drought, and resist pests and diseases, with rabbits and deer often sparing their raspy foliage. Their only universal need is abundant sunlight. They do and look well combined with other sun-loving meadow and prairie perennials such as switchgrass (Panicum virgatum) and blazing stars (Liatris spp.).

Black-eyed Susan (Rudbeckia hirta)

This eastern North American native lifts archetypal gold-petalled, black-coned flowers on 2- to 3-foot stems from late spring until frost, above rosettes of furry tongue-shaped leaves. Numerous garden forms are available, including so-called Gloriosa Daisy types, with especially large blooms that are often heavily stained with maroon. Named cultivars include ‘Cherokee Sunset’, whose huge double blooms carry various shades of burgundy and orange; ‘Prairie Sun’, with yellow, amber-haloed, green-coned blossoms; and ‘Indian Summer’, an enormous golden-yellow form. Compact forms such as ‘Toto’ and ‘Rustic Dwarfs’ fit nicely where space is more limited (including containers). All forms tend to be short-lived, in most cases behaving as biennials or annuals.

Brown-eyed Susan (Rudbeckia triloba)

Also short-lived, this relatively little-known biennial or perennial from central and eastern North America makes a highly rewarding and colorful garden subject in USDA zones 3 to 9. Borne from summer through fall in many-flowered clusters, the blooms resemble miniature black-eyed susans. Some forms such as ‘Prairie Glow’ have red-marked flowers reminiscent of Gloriosa Daisy forms of Rudbeckia hirta. Both of these short-lived species possess exceptional drought tolerance and self-sow freely if allowed.

Orange coneflower (Rudbeckia fulgida)

Most familiar in the form of cultivar ‘Goldsturm’, orange coneflower spreads by underground rhizomes and by seed to eventually occupy large swaths of garden. Many ‘Goldsturm’ in cultivation are actually imposters, with rangier stems and smaller flowers than the 2-foot-tall original. Whatever the variety, orange coneflowers produce gold-petalled, brown-coned blooms from July until frost, attracting loads of pollinators along the way. Dwarf selections such as foot-tall ‘City Garden’ and 15-inch ‘Little Goldstar’ work well in tighter spaces. All forms of this eastern North American native thrive in moist well-drained soil, but also do fine in drier sites. Winter hardiness is from USDA zones 3-9. Sweet coneflower (Rudbeckia subtomentosa) gives the effect of a somewhat taller, lankier, non-running Rudbeckia fulgida, with pure yellow rather than orange-yellow petals. The petals are furled into funnels in the cultivar ‘Henry Eilers’, lending it a novel look. Missouri coneflower (Rudbeckia missouriensis) also bears a summer-through-fall bounty of yellow, dark-coned blooms on clumping rather than spreading plants. The densely hairy, relatively slender-leaved, highly drought-tolerant plants top out at around 30 inches and do best in zones 4 to 9.

Cutleaf coneflower (Rudbeckia laciniata)

Here is the rudbeckia to grow if you want to make an architectural statement. Large eye-catching expanses of bold deeply cleft leaves bring forth towering stems crowned with yellow-petalled, green-coned blooms. The young leaves make good eating in stir-fries and other dishes. Flowering occurs from late summer into fall. Plants can spread vigorously underground, so either give them plenty of room or choose a less rambunctious selection or hybrid such as ‘Herbstsonne’. The double-flowered cultivar ‘Goldquelle’ is also relatively well behaved, especially compared to ‘Hortensia’, a rampant double-flowered selection that often goes under the name ‘Golden Glow’. This adaptable species from eastern and central North America does well in USDA zones 3 to 9. Also quite architectural is the south-central U.S. native commonly known as great coneflower, (Rudbeckia maxima). Drawing considerable attention in spring with its immense gray-green cabbage-like basal leaves, it produces flowers with prominent thimble-shaped cones on near-naked 5-foot-plus stems in summer and fall. Happiest in relatively moist, humus-rich soil, it sometimes fails for no discernible reason, even well within its zone 5 to 9 hardiness range.

About Russell Stafford

Hortiholic and plant evangelist, Russell Stafford, transplanted his first perennial at age 7 and thereby began a lifelong plant addiction. He is the founder and custodian of Odyssey Bulbs (and Odyssey Perennials), an online nursery specializing in cool and uncommon plants. Russell also works as a horticultural consultant, freelance writer (Horticulture and The American Gardener magazines), and garden editor. He formerly served as Curator and Head of Horticulture at Fernwood Botanic Garden in Niles, Michigan and as the Horticultural Program Coordinator at the Center for Plant Conservation, then located at the Arnold Arboretum in Jamaica Plain, Massachusetts. His academic degrees include a masters in forest science from Harvard University.

Shrubby Mallows

Everything has a season and midsummer is the time for mallows.  If the word “mallow” does not ring a bell, think of hollyhocks, okra and hibiscus.  All are part of the large mallow or Malvaceae family, with five-petaled flowers that look like crepe paper and distinctive central staminoid columns.  The familiar hollyhock flower is an archetypal mallow bloom.

Some mallows, like rose of Sharon, are true shrubs.  Others, including swamp mallow (Hibiscus moschuetos) and tree mallow (Lavatera arborea and Lavatera trimestris) are not true mallows, but have shrubby growth habits that make them excellent landscape specimens.  Like their mallow relatives, the shrubby  mallows are on display now in gardens across the country.

Rose of Sharon

The botanical name for rose of Sharon is Hibiscus syriacus.  This is confusing, because the plants do not hail from Syria, but grow wild in parts of China and India.  Hardy in USDA zones five through eight, the deciduous shrubs also grow exceptionally well in home gardens, rising to a height of eight to 12 feet tall and six to 10 feet wide.  Roses of Sharon can also be trained in standard or tree form.  If you grow the plant as a shrub, it can also be kept to reasonable dimensions by pruning.

Species roses of Sharon boast blooms that are pink with a darker red central “eye zone”.  Breeders have had their way with the species and now varieties are available in colors ranging from pure white through a range of pinks, reds and blue-purples.  Single-flowered cultivars sometimes have the characteristic contrasting eye zones.  Double-flowered roses of Sharon are full and fluffy with a multitude of petals.

To say that roses of Sharon are unfussy is an understatement.  If you have a space that receives full sun or light shade, chances are the plant will grow regardless of the soil type.  Once the shrub is established, it will withstand drought, pollution, and the toxins secreted by any black walnut trees that happen to be nearby.  Four-legged varmints avoid them as well.

The hollyhock-like blossoms are lovely at this time of the year, and the seed pods that succeed them are decorative.  Though the leaves do not color up in fall, the branches add structure to the landscape in the cold weather months.

If roses of Sharon have one flaw, it is their prolific nature.  Older varieties self-seed with wild abandon, making it necessary to be vigilant about locating and grubbing out unwanted seedlings.  To avoid this problem, prune the shrubs after they flower.  You can also invest in newer types, like the popular ‘Lavender Chiffon’, that are better mannered and do not self-seed.

Swamp Mallow

Though not technically a shrub, perennial swamp mallow (Hibiscus moschuetos) grows like one, with a woody stem and somewhat branching habit.  Rising between three and seven feet, with a spread of two to four feet, the plants have an impressive appearance, with lobed, toothed green leaves that may be up to eight inches long.  The real glory of the swamp mallow lies in the plant’s large summer flowers, which feature the traditional hollyhock-like configuration in an impressively large size—sometimes up to six inches wide in species plants, and even larger in hybrids and varieties.  A mature plant can produce scores of blossoms at once and serve as an eye-catching specimen in a yard or garden.

Species swamp mallows, which are hardy in USDA Zones five through nine, boast white or pink blooms with darker central “eyes”.  Plant breeders have created highly commercial varieties and hybrids, like the Southern Belle group of Hibiscus moschuetos, all of which have “belle” in their varietal names.  These mallows have a slightly more compact stature—four to six feet tall—and slightly less compact blooms, with flowers ranging from eight to ten inches wide in shades of white, pink and red, with the characteristic dark “eyes”.    At three to four feet tall, ‘Kopper King’, a hybrid of swamp mallow and another mallow species, Hibiscus coccineus, is more compact still, with distinctive dark maroon foliage and huge, light pink flowers, each bearing a red “eye”.

True to the “swamp” part of its common name, swamp mallows like uniformly moist soil and sun to light shade.  In cold winter climates, the plants die back to the ground, but return once the growing season is underway.

Shrubby and Manageable

The small and manageable tree mallows (Lavatera arborea and Lavatera trimestris) also have shrubby growth habits.  The annual trimestris species is native to the Mediterranean and grows two to four feet tall and two to three feet wide, making them good specimen plants, container subjects or low hedges.   The hollyhock-like blooms open in summer, or, depending on climate, early fall.  Normally about two to three inches wide, the blooms are white or pink and sprout from the axils of the lobed green leaves.  Lavatera trimestris is often grown from seed and can be started indoors six to eight weeks before the last frost date.  The plants may also self-seed if the spent blooms are not deadheaded.

At three to six feet tall, Lavatera arborea is somewhat larger than the trimestris species, and is native to parts of Europe and northern Africa.  It is a perennial, but is only hardy in warm winter climates, so these tree mallows should be treated as annuals or overwintered indoors.  Like the trimestris mallows, Lavatera arborea blooms in mid to late summer, producing pinkish purple blooms that are attractive to pollinators.

Both tree mallows like full sun to light shade and moderate moisture levels. Gardeners with heavy clay soil should add organic material, like Fafard® Garden Manure Blend, to give lavateras a good start.  As with other shrubby mallows, the tree mallows are easy to care for and provide lots of floral beauty for a relatively small investment of time, effort and money.

 

About Elisabeth Ginsburg

Born into a gardening family, Elisabeth Ginsburg grew her first plants, a healthy stand of Hollyhocks, as a young child. Her hands-on experiences range from container gardening on a Missouri balcony to mixed borders in the New Jersey suburbs and vacation gardening in Central New York State. She has studied horticulture at the New York Botanical Garden and elsewhere and has also written about gardens, landscape history and ecology for years in traditional and online publications including The New York Times Sunday “Cuttings” column, the Times Regional Weeklies, Horticulture, Garden Design, Flower & Garden, The Christian Science Monitor and many others. Her “Gardener’s Apprentice” weekly column appears in papers belonging to the Worrall chain of suburban northern and central New Jersey weekly newspapers and online at http://www.gardenersapprentice.com. She and her feline Saki. “garden supervisor” live in northern New Jersey.