Alliums for shade

Flower & Garden Magazine, Oct-Nov, 1995 by Patricia A. Taylor

When choosing plants for shady settings, don't neglect to check out the Allium genus. That's right: alliums. While most alliums, including the culinary sorts such as onions, leeks and garlic, prefer sunny sits, there is a small but wonderful group of ornamental alliums that thrives in shade.

As with the sun lovers, these alliums are rarely bothered by garden pests, including deer, which do not enyoy the pungent taste of either the flowers or the foliage. They're exceptionally carefree and colorful as border plants or cut flowers.

All the alliums mentioned in this article are suitable for Zones 4 through 8 (where average winter lows range from minus 30 degrees to 20 degrees). In addition, two - the lavender globe lily and ramson - will do well in warmerr areas where winter lows are only slightly below freezing. The alliums that follow are listed in their order of bloom in may Princeton, New Jersey, garden.

Lebanon onion (Allium zebdanense) This gorgeous allium is covered with large, brilliant white flowers from late April to mid-May. An ideal plant for a dry, woodland shade setting filed with humus-rich soil, it grows between 12 and 16 inches in height. The Lebanon onion is especially beautiful when planted under shrubs that are late to leaf out or among hostas. Within two weeks after the last bloom fades, the plant goes completely dormant.

Turkestan onion (A. karataviense) A great plant for the front of the border, the Turkestan onion features plump, dark green foliage that forms ground-hugging arches. In the midst of the unusually shaped leaves, eye-catching balls of pinkish white flowers appear in May. The blossoms last for up to three weeks and then leave a handsome seed head before fading away. My plants vary in height from 6 to 10 inches and do well in partial shade where they receive four hours of direct sun.

Lily leek (A. moly) Mark McDonough, an enthusiastic collector of unusual alliums, says lily leeks are especially appropriate for areas of shade and dry soil. Mine, however, are placed in a slightly moist situation where they thrive and multiply. Their starry, sun-yellow flowers grow 12 to 18 inches tall and look terrific with blue pulmonarias and pink fringed bleeding hearts in a moderately shaded May border.

Ramson, rampion (A. ursinum) Betty Eyles of Surrey, England, planted half a dozen bulbs of this plant about 30 years ago and now has hundreds in her dry, deeply shaded woodland garden. Ramson is not only the most shade-tolerant but also the most rampant allium described in this article. While care should be exercised in introducing it into some gardens, it is perfect for difficult, shaded places where little else will grow. In spring, pretty white flowers atop 12- to 18-inch stalks pop up among the dark green foliage, which resembles that of a miniature hosta.

Nodding onion (A. cernuum) Although it is native to rocky slopes and dry hillsides across a wide swath of North America, the easy-care charms of this extremely attractive flower are just beginning to be recognized. Shade gardeners particularly appreciate the nodding onion's ability to flower with as little as two hours of direct sun. The plant is quite adaptable, growing 12 to 24 inches high in exposed rocky beaches, cool mountain woods or dry, open woods. In bud form, the flowers resemble large white drops; the buds cascade open into a lacy spray of white, pink, rose or lilac flowers in midsummer. A few named cultivars have worked their way into the nursery trade; I have tried several and find that none are markedly superior to the species.

Lavender globe lily (A. senescens, often sold as A. tanguticum) When I saw the phrases "flowers are long-lasting," "foliage stays attractive all season" and "rarely seen in American gardens" applied to the lavender globe lily in the McClure & Zimmerman catalog several years ago, I immediately ordered the plant - to my great pleasure. This allium grows 18 to 30 inches tall and has dark green, straplike leaves. Round balls of lilac flowers appear in mid-to late summer. The clumps increase in size each year and mine have reached the point where they are large enough to produce a succession of bloom for six weeks. My plants grow in a lightly shaded setting with four hours of direct sun.

Wild leek, ramp (A. tricoccum) Native in cool, deciduous woods from New Brunswick to North Carolina and as far west as Iowa, this 8- to 10-inch plant will bloom in heavy shade. Its leaves are considered an early spring taste treat. After the leaves wither and disappear, stalks topped with greenish white flowers appear in late June or cerly July. In their book Gardening with Native Wild Flowers, authors Samuel B. Jones Jr. and Leonard E. Foote report that there is a food festival devoted to these bulbs in the North Carolina mountains every year.

Thunberg onion (A. thunbergii) The purple flowers on this 8- to 12-inch-tall late bloomer don't even begin to open until late October. Allium collector McDonough says that at his previous residence in Seattle, the Thunberg onion flowered into December. In Massachusetts, where McDonough now resides, its blossoms last well into November.