Bulb Specialist Russell Stafford on the Best Spring Bulbs

Iris reticulata 'Michael's Angel'
The clear blue color of Iris reticulata ‘Michael’s Angel’ pairs beautifully with golden crocus.

Flower bulbs can’t be beat for bringing bursts of color to the garden. And they do it in such delightful fashion – their shoots thrusting up almost magically from the seemingly unoccupied ground in sudden crescendos of bloom. Then, just as suddenly, they pass from the scene, returning to the ground to wait out the months until their next brief fling.

The Siberian trout lily 'Altai Snow' is rare but worth seeking out.
The Siberian trout lily ‘Altai Snow’ is rare but worth seeking out.

Most garden bulbs (which botanically speaking comprise plants that grow from tubers, rhizomes, corms, true bulbs, or other underground storage organs) owe their fast and furious above-ground lifestyle to the short growing seasons that prevail in their native haunts. Many hardy “bulb” species, for example, hail from regions that receive most of their annual precipitation from late fall to early spring. The steppes and uplands of Central Asia – the ancestral home of many garden bulbs – are a place of long dry summers, cold bitter winters, and brief springs. Long, arid summers also characterize the climates of the bulb-rich Mediterranean and South African Cape regions.

Other bulb species are native to localized plant habitats that experience seasonal shortages of moisture or sunshine. Deciduous woodlands are the spawning ground of many of the most familiar shade-loving bulbs, which complete their above-ground growth in early spring before the canopy chokes out rain and sunlight.

Whatever their land of origin, most hardy bulbs need relatively moist, cool to cold winters and relatively dry summers, developing their roots in late autumn and winter and putting in an above-ground appearance for only a few weeks in spring or fall. Frost-tender bulbs, on the other hand, often come from regions in which rainfall and growth are concentrated in summer.

Corydalis, such as this Corydalis malkensis, come in many forms, all beautiful for spring.
Corydalis, such as this Corydalis malkensis, come in many forms, all beautiful for spring.

This is something to keep in mind when placing bulbs in the garden. Of course, a massed annual bedding display of hybrid tulips or hyacinths can be great fun and will work in just about any reasonably good soil. But a perennialized planting of less highly bred bulbs, artfully deployed in the appropriate garden habitat, can be equally compelling. Any garden niche that roughly mimics the conditions of a Central Asia steppe or a
Mediterranean chaparral or a temperate forest understory is fair game for a scattering of naturalized bulbs, which mingle beautifully with herbaceous and woody perennials that derive from the same natural habitat.

Reticulated irises (Iris reticulata and its hybrids) and “species tulips” (such as Tulipa humilis) make natural companions for penstemons, dwarf campanulas, plumbago (Ceratostigma plumbaginoides), low sedums, and other perennials that occur naturally in rocky steppe habitats. Likewise, crocuses, colchicums, cyclamens, and tuberous anemones look right at home with lavender, perennial candytuft (Iberis sempervirens), shrubby sages, and other small shrubs from the Mediterranean. And just about any partly shaded garden niche could benefit from a colony of woodland bulbs such as corydalis (including Corydalis solida) and trout lilies (Erythronium spp.).

A sunny garden site that dries out somewhat in summer is likely to be favorable for most sun-loving bulbs. In areas that are subject to summer rain and humidity, a well-drained soil works best. Rock gardens and troughs; embankments; wall plantings; sandy berms – all are ideal locations for grape hyacinths (Muscari spp.), ornamental onions (Allium spp.), and other steppe and Mediterranean natives. Quite a few sun-lovers (including many fritillaries and irises) absolutely require a dry summer rest, rotting away in warm moist conditions. Conversely, most woodland bulbs are relatively unfussy, thriving in just about any partly shaded site.

Species tulips (Tulipa bifloriformis shown) are often reliable perennials that spread over time.
Species tulips (Tulipa bifloriformis shown) are often reliable perennials that spread over time.

Whatever their favored exposure, bulbs tend to do best in relatively rich soil, and will usually benefit from a sprinkling of high-potassium fertilizer in early fall or spring. For excessively dry or heavy soil, incorporate a good amendment for fertility such as Fafard® Sphagnum Peat Moss and/or Compost. A general rule of thumb is to plant bulbs at a depth of 2 to 3 times their diameter (from the soil surface to their tips). Bulbs (such as crocuses and tulips) that are favorite morsels for chipmunks and squirrels may need protection such as a hardware cloth barrier (or interplant them with bulbs that rodents tend to avoid, such as narcissus and alliums).

The right bulbs in the right place will add a seasonal spark to any garden. Plant some this fall to reap your reward next spring, and beyond!

All About Fall Bulbs (Plant them in Late Summer!)

Autumn crocus
Autumn crocus (Colchicum autumnale) adds bright color to fall gardens. (Image by Lestat)

It’s been a long, harsh season. Your garden, and your spirits, lag. But just when you despair that the garden will never return to glory, that the doldrums will drone on forever, a sprightly purple crocus appears among the yellowing foliage of your waning perennial border, and your spirits suddenly leap at the joyous thought that it’s . . . fall?

Yes, indeed. They bloom in late-summer or fall. For although crocuses and other bulbs well deserve their reputation as harbingers of spring, they merit equal celebrity as heralds of autumn. Like their spring-blooming kin, fall-blooming bulbs are admirably suited for bringing splashes of color to dull borders, or for naturalizing in a woodland edge or lawn. And now’s the time to purchase and get ready to plant your fall bulbs for August or September planting. (Soil amended with Fafard Premium Natural & Organic Compost will offer more fertile ground for your bulbs.) Within just weeks they will be on glorious display providing instant gratification; what more could one ask?

Fall Crocus

Violet crocus
Brilliant violet-blue blooms distinguish Crocus speciosus ‘Aino.’

Of the dozens of species of hardy fall-blooming crocus, none heralds autumn more exuberantly than showy crocus, Crocus speciosus. Vigorous and adaptable, this Eurasian native does well in sun or partial shade, tolerates most well-drained soils, and weathers practically anything fall throws its way. It flaunts violet, 2-inch-long flowers in September, October and sometimes November, and like most hardy autumn crocus, it leafs out in spring, thus escaping winter damage. The blossoms open in sunlight to reveal orange-scarlet stigmas and yellow anthers. Among its many noteworthy cultivars are ‘Albus,’ a beautiful, late-blooming white selection; the October/November-blooming, pale-lavender ‘Aitchisonii’; and ‘Aino,’ distinguished by its deep-violet-blue blooms and superior weather resistance.
The title of most distinctive hardy fall-blooming crocus might very well go to iris-flowered crocus, Crocus banaticus. The remarkable lilac-purple flowers have an elegant, iris-like form and bloom in late September. Equally distinctive are its unusually broad spring leaves, which lack the central stripe typical of its kin. This Crocus also departs from most other crocus in its love of moisture (it frequents damp meadows in nature) and tolerance of partial shade.

Crocus pulchellus
Delicately suggestive of spring, the flowers of Crocus pulchellus ‘Inspiration’ bloom in mid-fall.

The eminent garden writer (and gardener) Elizabeth Lawrence remarked that the hardy ‘beautiful crocus’ (C. pulchellus ) is “well-named, for the flowers are so adorable that it is hard to describe them without sounding foolish.” Even more foolish, however, would be to forego the pleasures of this breathtaking species whose rounded, fragrant, lilac-blue, orange-throated, violet-veined flowers are generously borne in October on white “stems.” Sun to partial shade and well-drained, not overly dry soil will suit it fine. And its many excellent forms, which include the white ‘Michael Hoog,’ clear-blue ‘Inspiration,’ and pearly-lilac ‘Zephyr’, will naturalize through self-sowing.
And the list of outstanding fall-blooming crocus goes on: C. goulimyi with its lilac-blue, scented chalices in October and November; the gold-throated, September/October-blooming C. kotchyanus, hardy, vigorous, and self-sowing; C. medius, whose 2-inch-long lilac-purple blooms in October are among the showiest of the fall crocuses; and C. nudiflorus, another large, purple-flowered, September/October-blooming species that likes moist soil. All these and more could and should be in more of our gardens, particularly in sites with the loamy, well-drained soil and full to partial sun they prefer.

Fall Colchicum

Rosy Dawn
Colchicum ‘Rosy Dawn’ is a real looker in lavender-pink and white.

Curiously, the common “autumn crocus” is not a crocus at all. Although Colchicum autumnale superficially resembles its namesake, it actually belongs not only to a different genus but also to a different family (Colchicaceae rather than Iridaceae). But it joins the fall crocuses as one of the most outstanding ornamentals for the late-season garden, bearing goblet-shaped, lilac-pink, 1.5-inch-long flowers from late August through September. It has also given rise to many splendid cultivars, including  the white ‘Album’ and double white ‘Alboplenum.’ A self-reliant species, it — like many others of its genus — succeeds in almost any well-drained, moisture-retentive soil in sun or partial shade, where it makes a great companion for fall-blooming woodland-edge perennials such as Japanese anemone (Anemone japonica) and toad lily (Tricyrtis spp.). All parts of the plant are poisonous (containing the compound colchicine). Its toxicity does carry some benefits, however: it is unpalatable to most pests, including deer, although slugs will occasionally browse its buds and leek-like, spring leaves.
Fafard Premium Natural & Organic Compost Blend packAlso occasionally found in American gardens is showy colchicum (C. speciosum), which earns its moniker by abundantly producing fragrant, 3-inch chalices of raspberry-tinged purple-pink (often with white centers) in September and October on 4-inch “stems.” Equally noteworthy is its cultivar ‘Album,’ whose pearly flowers resemble white tulips, and its many garden hybrids, of which ‘The Giant’ and the aptly named ‘Waterlily’ are the least scarce. Dozens of other laudable hybrids and species, however, are virtually absent from American horticulture, such as the delicate ‘autumn crocus’ (Colchicum byzantinum).
Some gardeners bemoan the bare ground created by showy colchicum’s handsome, foot-long, leek-like foliage, which mantles the ground in spring before withering indecorously in early summer. Wiser hands, however, tuck C. speciosum among late-growing perennials or vigorous ground covers such as plumbago (Ceratostima plumbaginoides), smaller hostas and ferns that cover the fading leaves. Summer annuals also make great companions.

Fall Golden Crocus

Sternbergia lutea
The yellow flowers of Sternbergia lutea brighten fall borders. (Image by Eugene van der Pijll)

Sternbergia lutea is yet another fall-blooming bulb masquerading under the common name of crocus (golden crocus, in this case). One of the few yellow-flowered fall bulbs, it lifts its goblet-shaped, 2-inch-long blooms on 4-inch stalks in September and October, perfectly complementing the blue flowers of Crocus speciosus. The leaves appear immediately after bloom, and plants appreciate loose mulch (such as evergreen boughs) over winter. Because of its largely Mediterranean origins, this species prefers sunny, sheltered, well-drained sites and detests summer dampness. It thus grows well in south-facing woodland edges, where encroaching tree roots absorb excess moisture. Long appreciated in gardens and nature (it is thought to be the Bible’s “lily of the field”), S. lutea is threatened in the wild, and should therefore be purchased only from reputable firms that supply nursery-propagated material. Although scarce in the trade, it is well worth searching for.

Autumn Snowflakes

September Snow
Elegant bells of white hang from the dark stems of Leucojum autumnale ‘September Snow.’

Many other hardy bulbs surprise us with fall blooms. Lovers of the spring and summer snowflakes (Leucojum vernum and L. aestivum) can enjoy an August to November flurry of the white, nodding bell-flowers of autumn snowflake, L. autumnale. Valentian snowflake (L. valentinum) boasts larger flowers (3/4- rather than 1/2-inch), but is somewhat more tender. Some rare but beautiful squills also bloom in fall, most notably Scilla scilloides whose plumy, 8-inch “spikes” of starry pink flowers appear from August through September (autumn squill, S. autumnalis, is also worth growing). Alliums also have their fall-blooming contingent, among them A. thunbergii (perhaps best known in its violet-flowered cultivar ‘Ozawa’) and A. senescens, which includes the beautiful, spiral-leaved ‘Glaucum.’ There’s even a fall-blooming snowdrop, Galanthus reginae-olgae, which will winter in a sheltered site. All these require light shade to full sun and well-drained, fertile soil.
So the next time you’re looking for something to perk up your flagging fall garden, consider the lilies of the field or one of the many other autumn-blooming bulbs. Then you, too, can celebrate the first crocus of fall.

Colchicum byzantinum
Fall-blooming autumn crocus (Colchicum byzantinum) add easy interest and color to late-season borders. (Image by Jessie Keith)