These underused bulbs brighten both spring and fall with their delicate beauty
by JOE ECK
EARLIEST SPRING BOASTS MANY SMALL BULBS of great beauty, scillas and chinodoxas, snowdrops and crocuses, often in a bewildering array of species and selected cultivars. In such a vivid crowd, the lowly leucojum is often overlooked, for it exists in only two species that are commonly grown, Leucojum vernum and L. aestivum, and of the two, only the former, the spring snowflake, possesses variants sufficiently distinct to have been given two dubious varietal names. Besides that, everybody knows what a crocus is, and a snowdrop, too. Leucojums most gardeners have never heard of. But if a law were ever passed declaring that leucojums—and particularly L. vernum—might not be grown in gardens, I would promptly become a lawbreaker. For in very early spring, on a wet March morning, clumps of it are not to be overlooked, whatever might be offered by treasured sheets of galanthus, or by a wealth of multiplying Crocus tommasinianus in watery, translucent lavender. And that is so for many reasons.
First, there is a curious sturdiness about L. vernum that contrasts pleasantly with its more fey spring counterparts. Seldom exceeding a height of six inches, it forms bold, leafy clumps of rich green. Almost simultaneous with this growth, slender flower stalks emerge, each bearing one or two down-hanging bells composed of six equal segments, all a pristine, waxen white that seems to reflect the mild spring sun. For all their modesty, however, there is something antic in the poise of the flowers, for each petal (sepal, actually) is curved outward at its tip, and sharp-pointed, the point accented by a dot of acid green that, upon close examination, turns out to be chartreuse yellow shaded to deep green. The effect, for so small a thing, is luminous, and the whole looks like a jester’s cap with outflaring flaps, the green dots serving for the bells. In flower, L. vernum seems to make everybody smile.
And there’s another special thing about L. vernum that the courts might consider. Whereas the slow emergence of snowdrops is watched over and measured by the gardener in millimeters from early January to March, spring snowflakes appear almost magically overnight, seeming true to their elfin nature. This may be in part because the low-lying, shady hollows they favor are not the first places, in spring, a gardener looks. Sometimes I even have to lift a thatch of partially decayed maple leaves from a crown, revealing almost fully grown leaves and flowers, all of a clear butter yellow. But a day or two in the sun, such as it is then, turns them green and upright.
If L. vernum, for all its charm, is rare in gardens, part of the explanation lies in the difficulty of establishing the dry bulbs in autumn, when most gardeners assume all bulbs should be planted. It can be done, though the viability of bulbs dug from the field is short, and so they should be ordered for very early delivery, in late August or the first weeks of September. Bulbs should be planted singly, about six inches apart and half as deep, in humusy, moist, even boggy, soil. Even so, prepare for disappointment the first year, since some of the bulbs will not survive, and others may languish for a year or two until they become established. Far better to plant “in the green,” while the plants are still growing, in late spring or early summer. Beg a clump or two from a fellow gardener, and separate and plant the bulbs as quickly as you can, within a day or two, preferably in cloudy or rainy weather. So planted, they never look back, and often bloom modestly the following spring, abundantly thereafter. Clumps will seldom need dividing, unless one is either greedy or altruistically inclined to share with others.
The other leucojum often grown by gardeners is L. aestivum, called the summer snowflake because it blooms much later, just as the leaves on the shade trees have unfurled. It certainly bears a resemblance to its spring cousin, but it is more remarkable for its differences, and therefore, for its different garden uses. It forms thick, black-green clumps of leaf to as tall as 20 inches, among which the flower stems, only a little taller, nestle. Each stem is surmounted by two or more delicate, nodding bells, with characteristic outflaring petals and tips of green, though this time they are unmixed with chartreuse. The flowers seem small, hardly what would be called showy. They are in fact each scarcely an inch across, but against the black green of the grasslike leaves, they glisten.
Like L. vernum, the summer snowflake flourishes in damp, humusy soil, and it will accept and even be grateful for dappled shade. It is therefore best established in the woodland garden among ferns, or perhaps in a hollow bay of the shrubbery, where its quiet, cool beauty will not experience much competition. Leucojum aestivum is a little easier to establish than L. vernum, but it is still best planted in the green. And since well-established, large clumps always look most beautiful, division should occur only when absolutely necessary. There is a slightly more vigorous, taller form, called ‘Gravetye Giant,’ though it is only marginally taller (by three or so inches) than the typical form. Get it if you can, but do not be very disappointed if you cannot.
It is a peculiarity of the genus Leucojum, which contains at best only 10 species, that the two most common are native to damp European woodlands and almost boggy meadows, while all the others inhabit dry, rocky slopes around the Mediterranean from Spain to North Africa. Almost in compensation for the arid deprivations of their homelands, what might be called the “other” leucojums are fey and rather fussy, but they all possess a tiny, refined charm that will appeal most to the rock gardener, or to those who grow winter- and spring-flowering bulbs in pans in the cool greenhouse. Once cultivated in either place, they are apt to become addictive.
Most commonly grown in this group is L. autumnale, which, as its name suggests, blooms from August to October. It is an airy, delicate little plant, producing fine, hairlike leaves of a deep, black-green and five to eight inches tall. Often, however, the first equally slender flower stems appear before the leaves even emerge, looking pathetically vulnerable until other leaves follow, eventually producing an ethereal little mass of flowers and leaves together. The flowers are tiny, scarcely one-quarter inch long and across, typically tinged with pink, though lacking any markings. A delightful form with even tinier growth bears flowers tinted a stronger pink—though still quite pale—which is usually given separate species status as L. roseum. I grew it for years, I am embarrassed to say, without perceiving the difference.
Three other species closely resemble L. autumnale, though they are scarcely grown except by specialists in rare bulbs. Leucojum tricophyllum bears tiny bells composed of white or pale pink, pointed and reflexed sepals, and L. longifolium produces equally small flowers with pure white, rounded petals. Both are very nice. But particularly worth seeking is L. nicaeense, which seems the most robust of the tiny leucojums, and also sets copious seed, which can achieve flowering age within three years. All three will begin blooming in late winter and continue through spring.
Though L. autumnale and the other species that resemble it are sometimes suggested for the rock garden, the planted wall, or for cracks in pavement, their particular cultural requirements really make them best grown in pots. All are native to arid Mediterranean climates and so demand both a very free-draining soil and a dry period in summer—what the old gardeners called a summer baking. In most of North America, these are conditions that can far more easily be guaranteed in a pot than in the open ground. And the fragile autumn-, winter-, or early spring-born beauty of the flowers both demands and richly repays the closest observation. So they are really at their best when established in shallow bulb pans, which must be kept in the hottest, driest conditions one can find throughout the summer, and moved into cool, frost-free conditions in winter. No need to worry about when to begin watering in autumn, for the bulbs themselves will tell you, by the surprise of a tiny, hairlike leaf or flower stem. You can get out the magnifying glass then, to see the beauty that is there, or you can wait for the more impressive show that is soon to come. H
For sources of plants featured in this article, turn to page 76.