Native Bulbs By Pamela Thomas

Try some of these unusual and noteworthy native geophytes, which are suited to a variety of gardens.
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Photo credits: Western trout lily by Michael S. Thompson; Dutchman’s breeches by David Cavagnaro.

Using native plants in the landscape comes naturally to me after working for several years as a horticulturist at Garden in the Woods, headquarters of the New England Wild Flower Society, in Framingham, Massachusetts. And although I still think of Dutch iris, daffodils, and tulips as stalwarts of the spring garden, there are many less commonly cultivated native North American bulbs well worth incorporating into traditional bulb plantings, perennial beds, or woodland gardens.

Collectively termed geophytes, bulbs are divided into various subcategories based on their specialized root structures. These include corms—swollen underground stems; true bulbs—modified leaves and scales usually with a papery covering; tubers—a mass of modified stem tissue with several points of growth; tuberous roots—swollen roots that serve as storage organs; and rhizomes—subsurface, horizontal swollen stems.

The diversity among North American bulbs is astounding. Here are a few of my favorites organized by habitat type and blooming time. I have focused primarily on eastern natives because my experience has been with them, but the chart on page 21 describes intriguing bulbs native to western North America.

Woodland Species

Bloodroot (Sanguinaria canadensis, USDA Hardiness Zones 3–9, AHS Heat Zones 9–1) is one of those harbingers of spring for gardeners in the Northeast, blooming just after skunk cabbage (Symplocarpus foetidus) and hepaticas (Anemone acutiloba, A. americana; these were formerly in the genus Hepatica).
Like many spring-flowering plants in the eastern deciduous forest, bloodroot rushes to complete its bloom cycle early to take advantage of maximum light conditions before the woodland canopy leafs out. Flowers appear in mid-April, preceded by a clasping pair of rounded, deeply lobed leaves that fold down and apart to unveil a single flower stalk of pure white, daisylike flowers with yellow centers. The flowers last only a short while, but the attractive deep green leaves persist and make a handsome low groundcover through the summer.
Bloodroot has a wide natural range from Nova Scotia to southern Manitoba, south to Texas and Florida, where it grows in shade or partly sunny conditions in moist woods, slopes, and floodplains.

Other spring-flowering bulbs ideal for the eastern woodland garden are Dutchman’s breeches (Dicentra cucullaria, Zones 4–8, 8–1) and squirrel corn (Dicentra canadensis, Zones 4–8, 8–4). Dutchman’s breeches are named for their mid-April flowers, which resemble white inverted pantaloons.

Opening a week later, squirrel corn’s pendant, white, bell-shaped flowers are similar to the popular Asian bleeding heart (Dicentra spectabilis), and the Appalachian wild bleeding heart (D. eximia) but are smaller and lack the red or pink coloration. Their fragrance is reminiscent of lilacs. The common name is derived from squirrels’ predilection for their tasty yellow, tear-shaped bulblets.

Dutchman’s breeches’ natural range is wide: from Nova Scotia and eastern Quebec south to Georgia, Arkansas, and Kansas, with a few disjunct western populations. Squirrel corn occurs naturally from southern Maine and Quebec, south to North Carolina, Tennessee, and Missouri. Both Dutchman’s breeches and squirrel corn have lacy fernlike foliage and do well in cultivation with shade or filtered light in moist, rich soils.

Another eastern woodland ephemeral that blooms in spring is the yellow trout lily (Erythronium americanum, Zones 3–9, 9–2). It represents one of 14 North American Erythronium species, many of them western in origin (for western native bulbs, see page 21). This species is widely distributed in moist woodland habitats from Nova Scotia and western Ontario south to Georgia and Florida. Emerging from small corms, the three-inch-long, elliptical green leaves are splotched brown in lovely batiklike patterns. The leaves appear in April, followed by bright yellow, solitary flowers whose petals curl backwards to reveal long, salmon-colored anthers. The flower’s throat is sometimes brushed in a burnt rust color. The bloom cycle is concurrent with trout fishing season, an association that gave rise to the plant’s common name.

Other early May bloomers in the woodland garden are the ephemeral spring beauties Claytonia caroliniana and C. virginica (both Zones 4–9, 6–1). C. caroliniana is found in woods and bottomlands from Quebec and Ontario south to Georgia. Claytonia virginica is found in moist woods from Nova Scotia to Minnesota, south to the mountains of Tennessee and Georgia. Claytonia caroliniana begins blooming a week or so ahead of C. virginica, but otherwise the two species are very similar with white to light pink, five-petaled flowers—sometimes with pink venation—borne in racemes on six- to eight-inch stems, with two to 15 blooms. Each flower is a half inch across and has rounded petals.

Both species have fleshy, succulent leaves characteristic of the portulaca family to which they belong. The linear leaves are arranged in opposite pairs along the stem around which they wrap. Claytonia caroliniana has a slightly wider leaf than C. virginica and it narrows to a more distinct petiole. The corms of spring beauties look like small hazelnuts with bumpy scales. Both species go dormant by summer, but in their prime, they look wonderful planted in large groups with bloodroot, Virginia bluebells (Mertensia virginica), maidenhair fern (Adiantum pedatum), and squirrel corn.…


Bulbs for Wet Spots

Another little-known plant I came to admire at Garden in the Woods is swamp pink (Helonias bullata, Zones 5–9, 9–5). The plants I know receive half a day of sun, and are growing at the edge of a pond, at first submerged in water, then in a muddy substrate as the pond edge subsides a bit. The plant forms rosettes of straplike foliage; its cold-tolerant maroon leaves give way to a new flush of short, fresh green basal leaves in spring, that lengthen over the growing season. A two-foot central flower stalk resembling a small drumstick rises in May or June. The elliptically-shaped flower ball displays pink tepals and lavender blue anthers with a fragrance that wavers between clove and jasmine. After several years, swamp pinks form multiple clumps. Divide them by gently pulling apart the thick, fleshy rhizomes after the plants are finished flowering. Swamp pinks are considered a threatened species in the wild, so be sure to look for nursery-propagated divisions if you want to grow this beautiful plant in your garden.

When the flowers of most eastern woodland bulbs have faded, feather fleece, also called eastern featherbells (Stenanthium gramineum, Zones 7–9, 9–7), comes into its own with a fine, floral display from August through October. Blooms open from bottom to top revealing a multitude of small, white, deeply incised flowers, arranged in open panicles on two- to four-foot stems. The lower sprays of drooping flowers lend a graceful, airy effect to the plant. It grows best in a sunny position in moist acid soil; its natural habitats include floodplain forests, moist woods, meadows, and coastal plain bogs. Its native range lies from Pennsylvania into Virginia, West Virginia, Alabama, and Texas.

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