Tag Archive: landscape shrubs

  1. The Best Hardy Camellias for the Landscape

    Camellias have been known to trigger acute plant envy in Northern U.S. gardeners.  If only those voluptuous blooms came on hardier shrubs that could withstand sub-zero temperatures.

    As a matter of fact, in some cases they do.  Although most camellias trace their origins to mild subtropical and maritime areas of East Asia, a few hail from chillier regions.  These cold-hardy camellias have contributed their genes to the development of new varieties that are as happy in Newport, Rhode Island as they are in Newport News, Virginia.

    Hardy Camellia Origins

    The hardiest spring-blooming camellias can even take snow flurries.

    Many of these winter-ready camellias owe their toughness to arguably the hardiest species in the genus, Camellia oleifera.  Widely cultivated in China for its seed oil, it occurs in the wild as far north as Shaanxi Province, where winter temperatures resemble those in south-coastal New England and the upper Mid-Atlantic.  In American gardens, it’s grown chiefly for its fragrant, white, 2- to 3-inch-flowers, borne in fall on large, shrubby plants furnished with oval, evergreen leaves that taper at the tips.  The handsome gray-brown bark makes an eye-catching winter feature.

    Camellia oleifera proved its hardiness in a series of bitterly cold winters that clobbered the eastern U.S. in the late 1970s.  Of hundreds of decades-old camellias at the National Arboretum in Washington, D.C., only a dozen or so survived – including several selections and hybrids of this rugged species. Subsequently, horticulturists have used Camellia oleifera to produce a number of comely cultivars that flourish into USDA Zone 6 (0 to minus 10 degrees F minimum temperatures).  Most of them produce pink or white, 3-inch-wide, single to double flowers in early to mid-fall (the earlier the better, so as to escape damage from Arctic spells).

    Recent introductions of Camellia japonica (shown) from Korea and northern Japan are very hardy. (Image by PumpkinSky)

    Camellia oleifera and its progeny are not the only hardy camellias on the block, however.  Recent introductions of Camellia japonica from Korea and northern Japan are also blessed with USDA Zone 6 hardiness.  Handsome year-round, they typically form dense 6- to 12-foot shrubs with lustrous, leathery, evergreen leaves and early-spring flushes of rich-red, 2- to 3-inch-wide flowers accented with yellow stamens.

    Thanks to these two species, gardeners in Zone 6 can now do the formerly unthinkable: enjoy a fall and spring garden display of showy camellias.

    Fall-Blooming Hardy Camellias

    The flowers of Camellia ‘Snow Flurry’ appear in mid to late autumn.

    Camellia ‘Autumn Spirit’

    Combining the showy flowers of the cold-tender Camellia sasanqua with the Zone 6 hardiness of Camellia oleifera, this highly prized hybrid bears zingy, double rose-pink flowers in early to mid-autumn, well before freezing weather threatens.  They’re lovely planted in combination with Colchicum ‘Waterlily’.  The dense, 8-foot plants have relatively small, dark green leaves.

    Camellia ‘Snow Flurry’

    Two of the hardiest white-flowered camellias (‘Plain Jane’ and ‘Frost Princess’) teamed up to produce this beautiful, tough-as-nails cultivar.  Frilly white pompons appear in early to mid-autumn on a fast-growing shrub that takes well to early spring pruning and winters reliably through Zone 6.  Combine it with Anemone japonica ‘Whirlwind’ and Ilex glabra ‘Ivory Queen’ for a fall symphony in white.

    Camellia ‘Survivor’

    Single white flowers open in mid-fall on vigorous 10- to 20-foot plants.  A hybrid of Camellia oleifera, it lives up to its name by consistently showing superior hardiness in cold-winter climates (to USDA Zone 6).

    Camellia ‘Winter’s Star’

    Named for the shape of its single, lavender-pink flowers, ‘Winter’s Star’ actually commences bloom in October, well before the onset of winter weather in Zone 6 (where it’s perfectly hardy).  It forms an open, conical, 10- to 12-foot shrub.

    Spring-Blooming Hardy Camellias

    The flowers of Camellia japonica ‘Bloomfield’ appear in late winter to early spring.

    Camellia japonica ‘April Remembered’

    No cold-climate camellia produces anything more luscious than the 5-inch-wide, semi-double, creamy-pink flowers of this remarkably hardy 1996 introduction from Camellia Forest Nursery.  It rapidly forms a vigorous, 6- to 10-foot shrub with large rich-green leaves.  If you garden in USDA Zone 6 but want bodacious Southern belle camellias, ‘April Remembered’ is the place to start.  And yes – it does bloom during the first warm days of April, or sometimes March.

    Camellia japonica ‘Bloomfield’

    Brilliant red flowers, lush foliage, and a large, dense, rounded habit make for one of best all-around camellias for Zone 6 gardens.  The single, 3-inch-wide blooms occur in flushes during mild spells in late winter and early spring.  The original plant – grown from Korean seed at Morris Arboretum in Philadelphia – is more than 12 feet tall and 6 feet wide.

    Camellia japonica ‘Korean Fire’

    Smoldering-red, six-petaled, 2-inch-wide flowers repeat from late winter through early spring, weather permitting.  Perhaps the hardiest camellia variety introduced to date, ‘Korean Fire’ is well worth trying in favorable microclimates into USDA Zone 5.  Plants grow to 10 feet tall and 6 feet wide.

    Growing Camellias

    All camellias grow best in acid, friable, humus-rich soil, with protection from north winds and strong sunlight. If you garden in sandy or heavy soil, give your camellia an extra-wide planting hole (at least 3 times wider than the root ball), and amend the backfill with Fafard Premium Natural & Organic Compost.  Spring planting and a yearly application of an inch or two of compost are also advisable, whatever the soil.

  2. Landscape Shrubs that Tolerate Salt

    Pink Sweet Pepperbush (Clethra alnifolia ‘Ruby Spice’)

    Salt can be a winter lifesaver for cars and pedestrians.  It can also be murder on the garden, sometimes literally.  Most de-icing salt contains sodium, which is toxic to many plant species.  Even when used sparingly, it can find its way onto the leaves and roots of nearby plants, disfiguring or killing them.

    One of the best ways to prevent salt damage to your garden is to use plant species that can handle some sodium.  The five shrubs described below are a great place to start. They’re perfect for framing and sheltering gardens in salt-exposed sites, such as roadsides and seashores.

    Chokeberries (Aronia spp.)

    Red chokeberry (Aronia arbutifolia, image by Abrahami)

    Brilliant foliage in fall, attractive clusters of white flowers in spring, and adaptability to a wide range of soil conditions are among the many merits of these handsome, disease-resistant shrubs from wetlands and uplands of central and eastern North America.  Red chokeberry (Aronia arbutifolia) doubles down on the fall color by covering itself with bright red berry-like fruits that persist into winter.  Happiest in moist soil, it slowly expands into suckering, 8- to 10-foot-tall clumps that are at their most luxuriant in full sun.  Its abundantly fruiting cultivar ‘Brilliantissima’ is particularly showy.  Smaller in size and less flashy in fruit, black chokeberry (Aronia  melanocarpa)  typically forms a thicketing, 3- to 5-foot shrub with glossy, rich-green leaves and edible black fruits.   Varieties of this exceptionally drought-tolerant shrub include the compact growers, ‘Autumn Magic’ and ‘Iroquois Beauty’, as well as ‘Viking’, which is cultivated for its relatively large, tasty fruit that’s excellent for juices, preserves, and baked goods.  The fruits of all chokeberries are favorites of birds.  Aronia arbutifolia is hardy to USDA Hardiness Zone 4; A. melanocarpa to Zone 3.

    Sweet pepperbush (Clethra alnifolia)

    The suckering, upright, 3- to 8-foot-tall stems of this eastern North American native are lined with lustrous, serrated, dark green leaves and topped in midsummer with fuzzy steeples of white or pinkish, root-beer-scented flowers.  The leaves turn bright yellow in fall, and the persistent, peppercorn-like fruits make a pleasant winter garden feature.  Sweet pepperbush comes in numerous varieties, including low-growing ‘Hummingbird’, pink-flowered ‘Ruby Spice’, and late-summer-blooming ‘September Beauty’.  All forms do best in moist soil and full to partial sun in USDA Zones 5 to 8.

    Inkberry (Ilex glabra)

    Female Inkberry (Ilex glabra, Image by David Stang)

    Its leathery, salt-tolerant, evergreen leaves and rounded habit would recommend inkberry for eastern North American gardens, even if it weren’t native to much of the region.  Most varieties become leggy 6- to 8-footers with age, so you might want to opt for a compact, densely leaved cultivar such as the 4-foot-tall ‘Shamrock’.  Female inkberries produce small, black, relatively inconspicuous fruits in fall, although white-fruited ‘Ivory Queen’ is a notable exception.  All cultivars are hardy in USDA Zones 5 through 8.

    Bayberry (Morella pensylvanica)

    Female Bayberry (Morella pensylvanica, Image by Jessie Keith)

    Recently redubbed Morella pensylvanica, bayberry will no doubt continue to be known to gardeners under its former botanical name, Myrica pensylvanica.  A signature species of salt-sprayed coasts from the Maritimes to the Carolinas, it’s literally a natural for salt-tolerant plantings in the eastern U.S. (and an excellent choice for other locations in USDA Zones 3 to 7).  All of its parts – from the leathery, deciduous or semi-evergreen leaves to the waxy berries (on female plants) – possess a silver-gray cast and a pleasingly pungent fragrance, made famous by the candles that bear its essence and its name.  Mockingbirds, yellow-rumped warblers, and other songbirds feed on the fruits in winter.

    Lilac (Syringa spp.)

    Common lilac (Syringa vulgaris, image by Jessie Keith)

    Almost all Syringa species boast moderate to high salt tolerance, reflecting their origins in arid regions of Asia and eastern Europe.  Although best known in the form of the ever-popular common lilac (Syringa vulgaris), the genus includes numerous other garden-worthy species and hybrids, many of which are relatively scarce in gardens.  Among the best of these for hedging and screening are littleleaf lilac (Syringa pubescens ssp. microphylla ‘Superba’), well worth growing for its aromatic, pale pink flowers that appear in late spring and summer on dense, dainty-leaved, 6-to 8-foot plants; cutleaf lilac (Syringa protolaciniata), distinguished by its deeply lobed leaves, compact arching habit, and pale lilac-purple spring flowers; and Chinese lilac (Syringa × chinensis), which in its best forms (such as ‘Lilac Sunday’) weights its stems with armloads of pale purple flowers in mid-spring, a few days before common lilac hits its stride.  Any of the above would make an excellent screen or hedge in a sunny site in USDA Zones 5 to 8.

    Whatever their salt-tolerance, all your plants will do better if you take measures to build their soil and to reduce their exposure to sodium.  Apply an inch or two of Fafard Premium Natural & Organic Compost or several inches of shredded leaves in fall or spring to boost and maintain the levels of sodium-neutralizing organic matter in your soil.  In addition to its many other benefits, mulch also lessens surface evaporation, thereby increasing soil moisture and lowering salt concentrations.

    You can reduce the amount of incoming salt by screening planting areas with structures and salt-tolerant plants, by grading the soil to divert salt-laden surface water, and by using sodium-free de-icers, such as magnesium chloride, on your driveway and paths.  The right plants and the right care can go a long way toward making your garden safe from salt.

  3. The Best Reblooming Shrubs for Summer

    Panicle hydrangea blooms through much of the summer.

    Flowering shrubs do lots of good things in the garden, but their length of bloom often disappoints.  Exceptions do occur, with hybrid roses being the most obvious and ubiquitous example.  They’re not the only shrubs that bloom long and well, though.  Here are seven of the best of the rest.  Their individual flowers may not be as voluptuous as those of a hybrid tea rose, but in other respects – including habit, foliage, and disease-resistance – they more than hold their own.

     

    Littleleaf Lilac and Hybrids

    Littleleaf lilac has smaller blooms that rebloom in midsummer.

    Almost all lilacs are one-and-done bloomers.  Not so with littleleaf lilac ‘Superba’ (Syringa pubescens ssp. microphylla ‘Superba’).  Abundant clusters of sweet-scented, pale lilac-pink flowers open from reddish buds in mid-spring, a few days after those of common lilac.  Then, in midsummer, a miracle occurs, with a second flush of blooms developing on the current season’s growth.  Littleleaf lilac is also attractive out of bloom, forming a dense, rounded, 8-foot specimen clad in dainty, privet-like leaves.  Plant breeders have crossed ‘Superba’ with other lilacs to produce several repeat-blooming cultivars, including those in the Bloomerang® Series.   For maximum rebloom, plant ‘Superba’ and its offspring in full sun and fertile, loamy, near-neutral soil.  A spring top-dressing of Fafard® Premium Natural & Organic Compost is all to the good.  These lilacs do best in USDA Hardiness Zones 4 to 8.

     

    Summer Snowflake Doublefile Viburnum

    Summer snowflake is a reblooming doublefile viburnum. (Image by Russell Stafford)

    Viburnums, like lilacs, typically flower for only a couple of weeks per year.  One of the few exceptions is the remarkable ‘Summer Snowflake’ (Viburnum plicatum ‘Summer Snowflake’), whose terraced branches are frosted with flat clusters of white flowers from mid-spring to early fall.  It also differs from other doublefile viburnums in its relatively compact, narrow habit (5 to 7 feet tall and wide).  Although lacking the wide-sweeping drama of full-sized doublefile cultivars, such as ‘Mariesii’ and ‘Shasta’, ‘Summer Snowflake’ literally makes a better fit for foundation plantings and other niches where space is limited.  The leaves take on smoky maroon tones in fall.  All doublefile viburnums perform best in sun to light shade and humus-rich soil, in USDA Hardiness Zones 5 to 9.

     

    Weigela Sonic Bloom® Series

    Weigela Sonic Bloom® Pink offers bright color through summer. (Image by Proven Winners)

    Many weigelas throw a few flowers now and then in the months following their main late-spring display.  This has inspired plant breeders to develop new Weigela (Weigela hybrids) cultivars that rebloom not demurely, but with abandon.  Those in the Sonic Bloom® Series are reputed to produce several good flushes of showy, trumpet-shaped blooms not just in late spring, but throughout summer and early fall.  Sonic Bloom® weigelas flower in pink, purple, or white, depending on the variety.  These relatively recent introductions have yet to prove their mettle in many parts of the U.S. – but they’re well worth a try in a sunny spot in USDA Hardiness Zones 5 to 8.  At 4 to 5 feet high and wide, they won’t take much space while you’re putting them through their paces.

     

    Caucasian Daphne

    A parent of the variegated, briefly blooming Daphne × burkwoodii ‘Carol Mackie’, Caucasian daphne (Daphne × transatlantica) is in most ways superior to its popular offspring.  Where it particularly outdistances ‘Carol’ is in its repeat, spring-to-fall display of tubular, white, sweet-scented blooms.  The dainty, oval, semi-evergreen leaves are also attractive and are strikingly variegated in forms such as ‘Summer Ice’.  Most varieties of this outstanding daphne top out at about 3 feet tall, with their branches splaying with age (or with heavy snow).  It does well in sun to light shade in USDA Hardiness Zones 5 to 8.

     

    Panicle Hydrangea

    The flowers of ‘Pinky Winky’ panicle hydrangea darken in color as they age. (Image by Jessie Keith)

    Not many years ago, panicle hydrangea (Hydrangea paniculata) was represented in gardens almost exclusively by the mop-headed cultivar ‘Grandiflora’ (more commonly known as peegee hydrangea).  Today, numerous outstanding varieties of this exceptionally hardy species (USDA Hardiness Zones 3 to 9) have found their way into horticulture, including many with lacy, conical flower clusters rather than weighty mops.  Most Hydrangea paniculata cultivars bear white-flowered panicles from mid to late summer, but other flowering times and colors also occur.  Look for ‘Limelight’, with full flower-heads that age to chartreuse-green; ‘Pinky Winky’, an early- to late-summer bloomer that evolves from white to rose-pink; and the late-blooming (and magnificent) ‘Tardiva’, with large lacy spires of white flowers from late summer to frost.  These large shrubs can be cut back severely in early spring to keep them in bounds.  Dwarf varieties such as ‘Little Lamb’ require no size control.

     

    Butterfly Bush

    Sterile, seed-free butterfly bushes are just as pretty but don’t self sow.

    How can we not mention the ever-popular, somewhat cold-tender butterfly bush (Buddleia davidii) and its many hybrids, which draw in butterflies over much of summer with their steeples of fragrant blooms in a variety of colors?  Recent developments in the butterfly bush universe include the introduction of several compact, sterile cultivars with especially prolonged bloom and no pesky seedlings.  These include ‘Ice Chip’, ‘Lavender Chip’, and ‘Purple Haze’.  Buddleia davidii and its hybrids do best in full sun in USDA Hardiness Zones 5 to 9, and usually benefit from a hard early-spring pruning, even in areas where they don’t die back.

     

    Flowering Abelia

    Flowering abelia is a long bloomer that will flower up until frost.

    Popular in the Southeast and Mid-Atlantic regions of the U.S., flowering abelia (Abelia × grandiflora and kin) are small to medium shrubs that could be used much more in the northern fringes of their USDA Hardiness Zones 5 to 9 hardiness range.  Their dainty, fragrant bells – in various shades of pink or white – cluster on arching stems from midsummer into fall.  Small, oval leaves add to the delicate, fine-textured feel of these quietly attractive plants.  Most flowering abelias are evergreen to semi-evergreen into USDA Hardiness Zone 6.   In zones 5 and 6, flowering abelias often work well as winter die-back shrubs, resprouting in spring and flowering in late summer and fall.  In all hardiness zones they benefit from early-spring pruning of snarled or winter-killed stems.