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Growing Garden Gladiolus

Growing Garden Gladiolus Featured Image

Few gardeners feel ambivalent about common garden gladiolus (Gladiolus x hortulanus). In the decades since the first large-flowered hybrids were developed in the late 1830s, the tall flower spikes have been in and out of fashion many times. But glads and the gardeners who love them are nothing if not persistent. Even when horticultural fashion arbiters ignore the genus, the many-colored blooms show up in all kinds of places, from the end rows of vegetable gardens to carefully tended perennial borders and florists’ bouquets.

The tall garden hybrids are impressive, but the genus is full of other winning plants, including petite species and varieties that are well suited to container and small garden culture. Many species glads have an informal look that is more reminiscent of the wildflower garden than the florist shop. Some are also fragrant. All gladioli share the characteristic long, sword-shaped leaves and summer bloom time.

The following is a brief guide to some of the stars of the gladiolus galaxy.

Gladiolus Grandiflora Hybrids

These are the plants that come to mind when most people hear the word “gladiolus.” All grow from corms that are tender in cold winter climates. Standard grandifloras soar between 3 and 6 feet tall. The trumpet-shaped individual flowers, which can be up to 6 inches wide, open from the bottom of the spike to the top. Vendors carry scores of named varieties in just about every imaginable color. Bi-colored glads are available in an amazing array of combinations. Breeders have also developed shorter, dwarf varieties, including the vividly marked “butterfly” types, which reach only 1 to 3 feet.

Gladiolus Primulinus Hybrids

Primulinus Gladiolus
Primulinus Gladiolus

These plants, formerly known as Gladiolus primulinus, are now classified as Gladiolus dalenii. Somewhat shorter, at 2 to 4 feet tall, the individual blossoms are hooded, rather than open like the grandiflora types. They also tend to be smaller and less crowded on the stems, giving the plants an informal feel. The primulinus glads are especially useful to cold winter gardeners, because they are hardier than grandifloras. Some varieties, like golden-apricot ‘Boone,’ are cold hardy to USDA zone 6.

Gladiolus Nanus Hybrids

Nanus Gladiolus
Nanus Gladiolus

Also smaller and less formal than the grandifloras, the Nanus Hybrids, bred from Gladiolus nanus, bear up to three slim flower stalks with up to ten relatively small individual flowers. These cold-tolerant miniatures may also feature distinctive markings.

Byzantine Gladiolus

Gladiolus communis var. byzantinus
Gladiolus communis var. byzantinus

Native to the Mediterranean, Gladiolus communis var. byzantinus blooms somewhat earlier than grandiflora types and is also more cold-tolerant. The 24- to 36-inch stems are slender and arch gracefully, bearing ten to twelve individual, open magenta flowers per stem. Byzantine glads bloom earlier than their large-flowered relatives and naturalizes readily. They are fixtures in old southern gardens and have often been passed along from gardener to gardener.

Abyssinian Gladiolus

Abyssinian gladiolus
Abyssinian gladiolus

Formerly known as Acidanthera, Abyssinian gladiolus (Gladiolus callianthus ‘Murielae’) has a distinctive, orchid-like appearance and a pronounced fragrance. Introduced in the late nineteenth century, the blossoms feature sharply pointed white petals with dark purple centers. Abyssinian glads grow on slender stems that rise from 3 to 4 feet in height.

Growing Gladiolus

Gladiolus in basket tray
Dig tender gladiolus in fall and overwinter them in a cool, dry place.

Gladiolus corms should be planted 4 to 6 inches deep in rich, well-drained soil. Before planting, amend heavy clay soil with organic material like Fafard Garden Manure Blend or Fafard Natural and Organic Compost Blend. For container-grown specimens use a complete potting medium such as Fafard Ultra Potting Mix With Extended Feed. Tender gladiolus hybrids can be grown as annuals in cold weather climates. To keep desirable varieties from year to year, lift the corms in fall and store in a dry, frost-free location. Replant in spring after all danger of frost has passed. Grandiflora types may need stakes or other support to prevent the heavy flower stalks from flopping, but shorter varieties can stand on their own.

Gladioli are sometimes known as “sword lilies” for the sword-like shape of their foliage. Arm your beds and borders with these “swords” and they will cut through the summer garden doldrums.

Rock Gardening for Beginners

Callirhoe involucrata
Callirhoe involucrata is a charming, heat tolerant summer bloomer for the rock garden.

Rock garden plants have an elfin, seductive charm all their own. Hailing from windswept, mist-shrouded summits, rocky slopes, craggy coastlines, and other picturesque and often challenging habitats, they somehow embody the mystery and majesty of their native haunts. Make their acquaintance and you will almost certainly yield to their spell.

Clematis fremontii
Clematis fremontii is an unusual, attractive species fit for rocky garden spaces.

Just about any garden can accommodate at least a few of these beguiling rock-dwellers. Moreover, their diminutive size and their preference for rocky niches make them some of the best subjects for space-challenged gardens. Tucked into a patio wall, or nestled in a clay pot, or associating in an alpine trough, they excel at bringing character and ornament to garden nooks and crannies. They even work well in urban settings.

Growing Rock Garden Plants

Getting them to grow happily in a domesticated habitat is another matter. To simulate a boulder-strewn mountaintop can be a bit of a trick if you garden in central Manhattan. Fortunately, many popular rock garden plants are relatively undemanding, taking well to most well-drained soils (although varying in other requirements such as exposure and soil acidity). As for the fussier types, most do well in humus-rich, nutrient-poor, gritty soil that stays moist in spring and cool and relatively dry in summer. A little Fafard® Sphagnum Peat Moss makes a fine amendment for gritty soils in need of added organic matter. Of course, almost all rock garden plants do best (and look best) in the company of rocks, which buffer their roots from heat and their stems from cold and dampness.

Building a Rock Garden

If you garden in coastal or upland New England or the Rockies, your unamended back yard may make the perfect rock garden habitat. In less craggy regions, however, some modifications may be necessary. To create a large rock garden habitat on well-drained but stone-free soil, bury large flattish rocks at a slight upward angle with their tips exposed. Place the rocks in such a way that they suggest the edges of an underlying rock ledge. Surface groupings of a few rounded boulders also work well.

Sisyrinchium idahoense flower
Sisyrinchium idahoense offers delicate starry flowers over grassy foliage.

Build small rock gardens from scratch by burying rocks in mounded growing medium, or by sandwiching the growing medium between stone retaining walls. A mixture of equal parts topsoil, coarse sand or grit (such as calcined clay), and Fafard compost makes an excellent medium for many rock garden subjects. The same mix can be used to create growing pockets in existing stone walls. For a micro-garden that can reside on your patio or at your doorstep, buy or make an alpine trough – a tub-shaped planter specially designed for alpine plants (see how to build and plant one at this link).

Easy Rock Garden Plants

Among the seven best plants for beginning rock gardeners (or any rock gardeners, for that matter) are:
1. Fan columbine (Aquilegia flabellata) and other dwarf members of the genus Aquilegia. Hummingbirds adore them.
2. Campanulas, including Carpathian harebell (Camanula carpatica) and Dalmatian bellfower (C. portenschlagiana). Both do well in full to partial sun and any not-too-soggy soil.

Dianthus gratianapolitanus 'Grandiflorus'
Dianthus gratianapolitanus ‘Grandiflorus’ is an easy charmer for early summer rock gardens. (image by Jessie Keith)

3. Cheddar pink (Dianthus gratianopolitanus), alpine pink (D. alpinus), and others of the Dianthus tribe, featuring grassy leaves and fringed, spicy-scented flowers. Most prefer full sun and alkaline soil.
4. Beardtongues such as hairy beardtongue (Penstemon hirsutus) and pine-leaf beardtongue (P. pinifolius). Hummingbird favorites, they thrive in sun, acid soil, and low humidity.
5. Lewisia cotyledon and its many beautiful selections and hybrids. This native of Northwest mountains loves cool, gritty, lime-free soil, and an east- or north-facing slope.
6. Phlox stolonifera, P. divaricata, and other low-growing phlox. The two mentioned here are best in partial shade.
7. One of the most beautiful Eastern woodland natives, bloodroot (Sanguinaria canadensis), which occurs in nature in shady, rocky habitats. Double-flowered forms (such as ‘Multiplex) are especially beautiful, and relatively long-blooming.

Sanguinaria canadensis 'Multiplex'
Sanguinaria canadensis ‘Multiplex’ is a double-flowered ephemeral ideal for spring rockeries.

10 Terrific Flowers for Honey Bees

Rudbeckia lacinata 'Autumn Sun'
Rudbeckia lacinata ‘Autumn Sun’ is a late-summer bloomer that bees love.

The decline in honey bees (Apis mellifera) has heightened the popularity of honey bee plants. Many favorite flowers for honey bees, like sweetclover, thistle, alfalfa and dandelion, are Eurasian plants too weedy for flower beds. Thankfully, there are some beautiful summer garden flowers, many being  North American natives, which are also great nectar and pollen plants favored by these Old World native bees. Regional natives are also superb forage plants for regional bees.
Fafard Premium Natural & Organic Compost Blend packThe best honey bee plants provide a good supply of both sugary nectar and protein-rich pollen sought after by these and other long-tongued bees. Lots of beautiful garden flowers provide both in high quantities. Here are our top 10 favorites organized by bloom time. Choose one for each blooming period and you’ll have great bee blooms throughout the growing season! All are sun-loving and grow best in good soils with regular to good drainage. Amend with Fafard Premium Natural & Organic Compost Blend and feed with a fertilizer for flowers, such as Black Gold Rose & Flower Fertilizer, for best results.

Early Summer Bee Flowers

Pale Purple Coneflower (Echinacea pallida, perennial)Pale Purple Coneflower (Echinacea pallida, perennial): An elegant beauty with fine, drooping petals, the pale purple coneflower is a bee favorite that also produces seeds much loved by finches. A native of grasslands and savannahs across the Eastern United States, this tough coneflower will bloom for up to three weeks from June to July. When in bloom, its flowers will feed lots of bees. You might even see a few butterflies on them as well.

Achillea millefolium 'Strawberry Seduction'Common yarrow (Achillea millefolium, perennial): The bright, flattened heads of common yarrow are covered with tiny daisy flowers that bees really favor. Native to both Eurasia and North America, this plant attracts loads of pollinators no matter where it’s planted. There are many beautiful varieties for the garden; two of the better variants are the rich red ‘Strawberry Seduction’ (image left) and ‘Wonderful Wampee’, which has pink flowers that fade to nearly white. 

Summer Bee Flowers

Sunflower with beesSunflowers (Helianthus annuus, annual): Nothing attracts and feeds bees like good old sunflowers. Their massive and prolific blooms come in shades of yellow, gold, red and orange and give way to lots of oil-rich seeds enjoyed by seed-eating birds and humans alike. There are literally hundreds of varieties to choose with various flower colors, heights and flower sizes. The dwarf varieties ‘Little Becka‘ (image left; 3-4’ tall with gold and brown flowers) and ‘Big Smile’ (1-2′ tall with classic golden flowers with black centers) are choice selections for any garden.
Agastache Blue BoaBlue Giant Hyssop (Agastache foeniculum, perennial): The pretty spires of purple flowers produced by the giant hyssop become simply covered with bees. A native across the northern regions of North America, this fragrant perennial in the mint family it tough and very hardy. The hybrid Agastache ‘Blue Boa’ (image left by Terra Nova Nurseries) is an exceptional variety from Terra Nova Nursery that is exceptionally beautiful.

Monarda punctata and Salvia coccineaHorsemint (Monarda punctata, perennial): Few garden perennials draw bees as efficiently as the long-blooming horsemint. A native of much of the United States, this sun-lover produces tiers of unique pink to white bracted flowers through much of summer and into fall. The blooms of these fragrant plants last a long time and become completely covered with pollinators. Plant in very well-drained soil for best performance.

Echinacea Dixie BellePurple Coneflower (Echinacea purpurea, perennial): The popularity of purple coneflowers and their many hybrids serves as a testament to their beauty and resilience. All are a favorite of bees, and like the pale purple coneflower, seed-eating birds enjoy the seedheads that follow. The purple-pink daisy flowers begin blooming in summer and will easily continue into late summer and even fall if the old flowers are removed. Some of the better new variants for big, long-blooming flowers include ‘Dixie Belle’ (left, image by Terra Nova Nurseries) and the super heavy blooming ‘Pica Bella’
Black-eyed SusanBlack-eyed Susan (Rudbeckia spp., annual or perennial): Nothing says summer like a beautiful black-eyed Susan, and bees appreciate their prolific flowers just as much as we do. One to seek out is the heavy blooming dwarf ‘Little Goldstar’ (Rudbeckia fulgida var. sullivantii ‘Little Goldstar’).
 

 Late-Summer and Fall Bee Flowers

Aster oblongifolius 'October Skies'Asters (Symphotrichum spp., perennial): The pinks, blues and purples of late-summer and fall aster flowers are a delight to all bees. There are so many wonderful varieties to choose from it’s hard to know where to start. The classic ‘October Skies’ (image left, Symphyotrichum oblongifolium ‘October Skies’) is a wonderful late bloomer with lavender-blue flowers and orange centers, and the dusty sky blue ‘Bluebird’  (Symphyotrichum laeve ‘Bluebird’) is an earlier bloomer with prolific flowers.

Eupatorium purpureumJoe-Pye Weeds (Eutrochium spp., perennial): This group of mid-to late-summer bloomers produces big, fuzzy heads of purplish-red flowers filled with nectar and pollen. Native across North America, many of the sun-loving perennials are adapted to moist ground. One of the finest garden varieties is Eutrochium purpureum ‘Little Red’ with its 4′ tall stature and pretty reddish-purple flowers.

SolidagoGoldenrods (Solidago spp., perennial): Lauded as one of the best bee flowers for late summer and fall, goldenrods become a buzzing mass when they open. In fact, goldenrod honey is a delicacy, known to be darker with a distinctive bite. Excellent garden-worthy goldenrods include the dwarf forms ‘Golden Fleece’ (Solidago sphacelata ‘Golden Fleece’) and ‘Baby Gold’ (Solidago ‘Baby Gold’).
With just a few of these garden beauties, feeding the bees all summer long is easy.

Corydalis: A Charming Spring Shade Perennial

Corydalis malkensis
Large swan-white blooms grace the cheerful Corydalis malkensis.

Endearing little sprites that carry flocks of dainty, spurred blooms above clumps of ferny divided leaves, tuberous Corydalis (crested larks) are among the most valuable early-spring “bulbs” for shade. These low-growing perennials have long been known to horticulture: the most familiar of the tribe, Corydalis solida, has been kicking around gardens since at least the sixteenth century. But in the last few decades, a multi-hued array of new species and cultivars has entered cultivation, taking the genus into exciting new territory.

Corydalis come in a veritable rainbow of colors
Corydalis come in a veritable rainbow of colors.

Spring Corydalis

The genus Corydalis also has a non-tuberous side, comprising several dozen perennials or annuals that grow from fibrous roots (rather than from swollen underground stems) and that remain in leaf all season (rather than disappearing shortly after bloom). These fibrous-rooted corydali include several species that are well worth a place in the ornamental garden – among them Corydalis lutea (now Pseudofumaria lutea), known for its profusion of yellow blooms and self-sown seedlings; and Corydalis flexuosa, whose luminous blue flowers and notorious heat intolerance have caused much lusting and despair among eastern North American plant enthusiasts. None of them, however, blooms in in early spring in hues ranging from blue to purple to bright red to pale yellow to white. For that, you’ll need Corydalis with tubers – especially Corydalis solida.

Corydalis ornata
Delicate blue flowers grace Corydalis ornata in spring.

Native to woodlands from southern Scandinavia to northern Spain to the Ural Mountains to northern Greece, Corydalis solida assumes a dizzying variety of colors and forms across its vast natural range. Until relatively recently, gardeners had to settle for the most common, rather nondescript purple-flowered forms. No longer. A wealth of cultivars in a broad and tantalizing range of hues now populate the pages of bulb catalogs. Among the oldest and most renowned of these new-wave corydali is the brick-red ‘George Baker’, one of a pack of red- and pink-flowered selections hailing from the mountains of Transylvania. (Caveat emptor – bargain-priced tubers sold under Mr. Baker’s name are often imposter seedlings bearing dingy-red blooms.) Other outstanding cultivars from the sunset side of the Corydalis solida color range include deep rose-red ‘Cantata’, rich lilac-pink ‘Sixtus’, and soft creamy-pink ‘Blushing Girl’. At the violet end of the spectrum are pale-lilac ‘Ballade’, denim-blue ‘Compact’, icy bluish-white ‘Evening Dream’, and the aptly named ‘Purple Beauty’. Milky-flowered ‘Snowstorm’ and the floriferous, late-blooming ‘White Knight’ are among the best white-flowered selections.

Corydalis solida 'George Baker'
The bright red flowers of Corydalis solida ‘George Baker’ are a real standout.

Most Corydalis solida cultivars readily self-sow (with the assistance of seed-dispersing ants), their seedlings often reverting to the muddy purple floral tones of the wild species. Remove such seedlings to keep them from crowding out their more colorful parents.
The world awaits a yellow-flowered Corydalis solida (reputedly such forms exist in the wild). Crosses with the sulfur-bloomed Siberian native Corydalis bracteata sometimes occur, however, their offspring (known horticulturally as Corydalis × allenii) producing pale creamy-yellow, lilac-brushed blooms and fetching, deeply cleft leaves. Corydalis bracteata and its fellow Siberian Corydalis gracilis also make excellent yellow-flowered garden subjects for areas that have long, cold, snow-locked winters.
Woodland Corydalis are habit-forming. Once you’ve discovered Corydalis solida and its hybrids, you’ll want to have a go at the many other garden-worthy species – perhaps Corydalis malkensis, with its voluptuous, gaping, swan-white blooms; or Corydalis kusnetzovii, which flowers in a beguiling shades of pale pink; or one of the brilliant-blue-flowered East Asian species (such as Corydalis ornata and Corydalis turtschaninovii). All thrive in partial shade and humus-rich soil; amend sandy or heavy soils with a good compost such as Fafard Premium Organic Compost or Fafard Canadian Sphagnum Peat Moss.
Real corydalis addicts will also want to explore some of the Central Asian species, which are typified by pink or white, chocolate-nosed flowers, blue-green foliage, and a preference for sunny, gritty-soiled niches that stay relatively dry in summer (such as a rock garden or trough). As with the woodland Corydalis, they present a wealth of delightful possibilities for the early spring garden.

The pretty Corydalis x allenii 'Enno' is a subdued but attractive variety for the spring garden.
The pretty Corydalis x allenii ‘Enno’ is a subdued but attractive variety for the spring garden.