Adored and spurned by gardeners, lily of the valley (Convallaria spp.) is the most familiar member of the family that bears its name (Convallariaceae). The fragrant, nodding flowers are celebrated in song and rhyme; the plant has religious as well as secular significance. One English legend states that it sprang up from the blood of St. Leonard, who fought a great dragon near Horsham. Another purports that the fragrance of the lily of the valley draws the nightingale from the hedge and leads him to choose his mate in the recesses of the glade.
Lily of the valley's relations—Solomon's plume and mayflower (Maianthemum spp.) and a host of others, including Solomon's seal (Polygonatum spp.)—are less storied but no less garden worthy. All currently reside in the Convallariaceae, though some botanists maintain their affinity with the larger, more inclusive butcher's broom family (Ruscaceae). Flowers of these diverse genera have sepals and petals that are indistinguishable from one another (known botanically as tepals). Most bear small, star-shaped flowers, though a few have nodding tubular flowers with six reflexed lobes. They are usually carried in terminal racemes or branched clusters called panicles, but exceptions like Convallaria and Speirantha display their flowers on separate basal, rather than terminal, scapes.
Lilies of the valley
Currently, three, or sometimes five, species of Convallaria are recognized by botanists: one in North America, and two to four in Eurasia. Lily of the valley is an easy groundcover that spreads freely and rapidly, if not recklessly. Its white rhizomes root at the nodes and form eyes, or pips, at regular intervals. In mid-spring, the pips produce sheathed stemlike scapes yielding two or three broad oval to lance-shaped leaves. As the leaves emerge, one-sided racemes bearing eight to fifteen bell-shaped flowers with six lobes emerge from the crown. The flowers are followed by green berries that ripen reddish orange in late summer.
Eastern and central European C. majalis is by far the most common in gardens. This wide-ranging species varies in size and stature based on its origin. European selections are the most common in cultivation, but a variety of unique foliage and flower forms from all corners of the world have been named.They are hardy in USDA Zones 4 to 8.
Convallaria majuscula (syn. C. majalis var. montana) is endemic to the Appalachian mountains of the eastern United States. This species is larger overall and more erect, with deep to sea green foliage and upright inflorescences. Though eminently garden worthy, this species is seldom cultivated, and no selections have been named. It is hardy in Zones 5 to 8.
The third universally recognized species is C. keiskei (syn. C. majalis var. keiskei), native to Japan, China, Korea, and Mongolia. Japanese lily of the valley, as it is called, is similar to the more familiar European species, but has smaller, thinner leaves. They are hardy in Zones 5 to 9. Selections include 'Snow Chimes', with a white edge on celadon green leaves that complements the fragrant white bell-shaped flowers, and 'Soft Stripes', which has irregular stripes, often with a frosted look that is unique to this variety.
Mayflowers and others
The genus Maianthemum (including plants formerly classified as Smilacina) consists of about 35 species widely distributed in temperate regions of the Northern Hemisphere, as well as in subtropical mountains of Asia and Central America. Of these, 19 are found only in China, where the genus achieves greatest diversity. The familiar inhabitants of the genus Maianthemum, called mayflowers, are fast-spreading groundcovers with corrugated, roughly heart-shaped sterile basal foliage and flowering scapes bearing two to three leaves. Clusters of four-tepaled flowers crown the thin flowering stems in early to mid-spring. Plants spread widely from thin white rhizomes and ultimately form extensive colonies with single leaves often outnumbering flowering scapes.
Solomon's plumes (formerly Smilacina spp.), are larger overall than mayflowers, with arching, often zigzag, leafy stems tipped with frothy panicles or (occasionally) racemes of six-tepaled starry white flowers. Plants spread from stout, sparsely-branched rhizomes to form open clumps. Foliage is clasping or bears short petioles and is generally deeply ribbed or pleated. Often the leaf margins are wavy, which adds to the show. Leaf color is generally deep green and somewhat glossy, but in some species the foliage may appear lacquered.
In the garden
Convallaria and Maianthemum are woodland plants, favoring abundant spring sunshine but requiring protection from burning rays in summer. Both tolerate deep shade but often flower sparsely there. They prefer humus-rich, neutral to moderately acidic soil that stays consistently moist. Established plants tolerate moderate drought but go dormant if dry conditions are chronic. In warmer zones, consistent moisture is particularly key to success.
Mayflowers and lily of the valley are excellent groundcovers for difficult sites, such as those with thin or rocky soil. Punctuate their dense carpets with ferns, bugbanes (Actaea spp.), and other tall woodlanders, or use them as a carpet under shrubs and flowering trees. In shaded spots with no foot traffic, mayflowers make a nice lawn substitute.
Solomon's plumes, meanwhile, need richer soil. They make elegant additions to beds, informal plantings, and woodland gardens. In ample light, they form dense clumps. In shade, the clumps are open and diffuse, lending a casual effect. Accent their upright stems with low plantings of foamflower (Tiarella cordifolia), bloodroot (Sanguinaria canadensis), and barrenworts (Epimedium spp. ). Ferns offer rich textural contrast. Try a drift of Solomon's plumes on a slope to mimic a foamy waterfall, or use taller species at the rear of a woodland bed along with sweeps of ferns, to meld the garden to the surrounding landscape.