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Home » Gardening Information » Indoor Gardening

Cape Cowslips (Lachenalia species)—Diverse and Adaptable South African Beauties

Plants & Gardens News Volume 15, Number 4 | Winter 2000

by Nancy Seaton, Illustration by Bobbi Angell

In the southwesternmost corner of Africa lies one of the richest botanical regions of the world—the Cape Floral Kingdom. The diversity of plant life in this relatively small zone rivals that of the Amazon for sheer numbers of endemic species per square mile—5,800 of the 8,600 known species in this kingdom are found nowhere else in the world—and 2,256 species are found on Table Mountain alone, forming a magnificent backdrop to the city of Cape Town.

The climate that supports this diverse flora is one of extremes: most of the region's yearly rainfall occurs during winter, while the summer there is characterized by drought. Cape plants have adapted to these harsh conditions in many ways. There are a wide variety of geophytes, for example, which retreat underground when the weather is unfavorable. Drawing on food reserves in their corms, rhizomes, tubers, or bulbs, geophytes lie dormant in the soil until the time is right to send up new leaves and flowers.

Among the thousands of geophytic species from South Africa, some of the most familiar to North American gardeners belong to the genus Lachenalia. These bulbous plants are commonly called Cape cowslips because of their superficial resemblance to certain members of the genus Primula (the cowslips). But in my mind they leave their namesakes in the dust. There are over 110 species of Lachenalia, and new ones have been discovered in the wild as recently as last year.

Bulb enthusiasts have prized Lachenalia for centuries. Descriptions date back to the earliest plant-collecting exploits of the Dutch East India Company, circa 1650. Initially called Hyacinthus (and by other epithets, too, since these were the days before Linnaeus' binomial nomenclature system created a uniform standard for botanical names), the bulbs were classified as a unique genus in 1784 when they were named after Swiss botanist Werner de la Chenal (hence Lachenalia).

Fanfare of Flowers

If you're looking to zip up your windowsill garden this winter, don't settle for the standard dosage of paperwhite narcissus. Lachenalia puts on a much more exotic display. The flowers are simply spectacular, ranging in color from the hot red of L. bulbifera to the ultraviolet-blue of L. namaquensis. And they last for weeks on end!

Lachenalia blooms are borne on single spikes or racemes atop a thick and usually mottled stem. Individual flowers have three basic forms: tubular, bell-shaped, and urn-shaped. A few species, such as L. arbuthnotiae, have a delightful fragrance that is both powdery and sweet.

Most lachenalias produce just one pair of leaves, though there are exceptions to this rule under cultivated conditions. Leaf form in the majority of species is wide and fleshy, but again there are exceptions. The leaves of L. contaminata, for instance, are thin and grass-like. Some species bear leaves with handsome dark spotting, while others display leaves that are notched with distinctive pustules (blister-like bumps).

L. aloides is the most commonly cultivated species in this country and the easiest to acquire from specialty growers. It's the most popular member of the genus probably because it's also the most colorful. To begin with, the leaves are marked with dramatic purple tiger stripes. Then there are the lovely tubular flowers—bright yellow accented with red and green. They appear in winter or early spring and hang down from a 10-inch, richly variegated stalk.

L. viridiflora is a horticultural favorite of mine. It is my first lachenalia to flower every year, blooming reliably around Thanksgiving. The flowers have an otherworldly color that's neither turquoise nor green. This plant is not as flashy as L. aloides, and its subtler charms give it greater cachet among garden insiders.

My new favorite species are L. mutabilis and L. framesii. I adore the tiny stature and delicate coloration of their individual flowers, which are more reminiscent of miniature orchids than of typical lachenalias. The centimeter-wide flowers of L. mutabilis have inner petals of chartreuse that extend towards outer petals of purple and maroon. Those of L. framesii have inner petals of magenta that extend beyond outer ones of green.

Growing Lachenalias

Lachenalias are an adaptable lot and relatively easy to cultivate. No pretreatment, such as a cold period, is required. In early autumn, place six to 12 bulbs in a 6-inch pot, depending on the size of the bulbs and their leaves. Plant the bulbs 2 to 3 inches deep. Lachenalias don't mind being crowded—in fact, they give a better display when planted this way. They are shamelessly promiscuous, producing numerous bulblets and offsets that can be separated and repotted.

South African bulbs are found in nutrient-poor, rocky soils. To simulate this in cultivation, always use a well-drained mix, with little or no humus. I grow bulbs in a mix of 3 parts bark, 1 part sand, and 1 part grit. In his Lachenalia Handbook, Graham Duncan recommends coarse sand mixed with a little fine compost.

Because lachenalias naturally grow in poor soils, there is no need to fertilize. In my experience, the plants do respond very well to low-nitrogen amendments. But err on the side of less fertilizer!

Water your bulbs once they have been repotted and not again until leaves appear above the soil surface. Then, as the pots dry out, give them a good soaking. Never allow the bulbs to dry out completely, as this could trigger dormancy or create unnecessary stress (you'll know there's a problem if the leaf tips start going brown). Too much water in a poorly drained soil, of course, spells one thing: R-O-T. "Love is not water" is a mantra for bulb growers.

Leaves will begin to yellow and wilt as the season progresses and temperatures rise (which is why these bulbs are cool-weather growers!). Reduce the amount of water you supply your bulbs until the plants are at this yellow stage, at which point, stop all watering. Never induce dormancy by withholding water before the plant is at this stage. If the bulb still has green leaves—water it! During summer dormancy, simply move your containers to a dry place.

Repotting can begin in August or September. Cool evening temperatures and warmer days will stimulate root growth in the fall. Daily temperatures should range between 50 and 70 degrees Fahrenheit. Lachenalia species can tolerate a little more shade than their other South African peers, but require as much sun as you can provide. If the bulbs are placed in a situation that is less than bright, they will lose their mottled leaf appearance and become lank.

Lachenalias are easy to grow from seed. Sow seeds thinly to avoid overcrowding. Keep at a temperature of 65 degrees Fahrenheit. They will germinate in 4 to 5 weeks. Don't disturb the seedlings until they go dormant at the end of their first growing season.

Threatened Habitat

Some species of Lachenalia are abundant throughout the Cape. Others have a narrow range of distribution—an entire community might exist on a single isolated rock outcropping. This sparseness of dispersal is the reason why new species continue to be discovered. But it's also the reason why so many are at risk. Their habitats are under constant threat from environmental flux (drought and fire), from human agriculture and development, and from invasive plants imported to South Africa from similar climatic regions, such as Western Australia.

Thus, one of the most pressing reasons to cultivate these bulbs, besides their charm, is for conservation purposes. Even if a species is "lost" in the wild, it is not lost to science, and the genetic material held in cultivated collections can be tapped for potential reintroduction into the wild. Adopt a Lachenalia—you'll not only be bringing a beautiful plant into your home, you'll be helping to protect the biodiversity of the planet.

Nursery Sources:

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