South African Bulbs on Display at UCI
Today’s open house at the UC Irvine Arboretum represents the only chance Southern Californians will have to view what is probably the world’s largest collection of rare South African bulbs. And many are at their flowering peak this month.
The bulbs featured at the arboretum open house may become a valuable resource for California gardeners. Because these plants developed in South Africa’s dry summer/wet winter climate, they are perfectly adapted for the Southland.
The bulbs are dormant when there’s no water, but come to life and flower after the winter rains. Unlike tulips and other Northern Hemisphere bulbs, South African bulbs require no winter chilling or spring irrigation.
The UCI Arboretum bulb houses are usually kept under lock and key, but today they will be unlocked so that visitors can see more than 1,000 different bulbous species planted in more than 25,000 pots.
Why is this amazing collection grown in pots surrounded by shade cloth and strict security?
Harold Koopowitz, arboretum director, explained that many of the species are rare; some are in danger of being lost in the wild. At the arboretum, the potted bulbs can be protected and monitored.
Since the arboretum is engaged in hybridization aimed at improving garden flowers and commercial cut flowers, haphazard pollination is forbidden. Honeybees, butterflies and hummingbirds cruise the blooms in the surrounding gardens, but the bulb houses are off limits. A shade cloth controls unwanted pollination.
Some of the bulb names sound familiar--iris and gladiolus, for example. But most of the flowers look alien and exotic. Their colors, forms, fragrances and textures truly ambush the senses.
Delicate flowers of Gladiolus gracilis are a true blue, surprisingly different from the lavender or purple of hybrid garden glads. Blooms of ferrarias, like miniature orchids, have distinctive fragrance, ranging from chocolate to mint to vanilla extract. The fuzzy leaf texture of a silvery-gray oxalis species invites the visitor to brush a hand across it to see if it feels as woolly and soft as it looks (it does).
The arboretum conducted tests to discover which South African bulbs are best for landscape use in California’s Mediterranean climate. They found that the best bulbs for normal soil conditions, with or without irrigation, are Babiana pulchra and its hybrids, Freesia muirii, Homeria flaccida, Sparaxis elegans, Sparaxis Irvine hybrids and Romulea leipoldtii.
For light soils that drain well, they recommend Gladiolus tristis, Homeria flaccida and Ixia maculata.
Their recommendation for the best all-around bulb, with or without irrigation, in natural or amended soil is Homeria flaccida. Called Cape tulips, homerias are durable bulbs that resemble yellow tulips.
One ongoing project at the arboretum is the crossing of winter-blooming South African gladioli with summer-blooming North American hybrid gladioli. The goal is a long-stemmed graceful flower stalk, smaller and lighter than the current heavy-stemmed summer glads--and one that blooms in the winter.
However, it doesn’t require much horticultural savvy to perceive an immediate problem: How can pollination take place when flowers are blooming in different seasons? Cold storage is the answer. The UCI Arboretum and Gene Bank has become a leader in cryogenic storage of rare and endangered species, as well as pollen, thus making such breeding possible.
Specializing in South African plants, the UCI Arboretum also displays more than 200 species of aloes, ranging from miniatures to giant trees. Most of the succulents are blooming now in stunning golds, reds and oranges.
Unusual flowering shrubs include the blue daisies of Felicia echinata, silvery mounds of helichrysums (source of everlasting strawflowers), and a weird spidery yellow euryops daisy. Sand dune plants, gazanias, arctosis, dudleas--this collection of drought-tolerant flowering plants boggles the mind.
As the Southland emerges from yet another substandard rainy season, South African plants take on special significance.
“Whether we like it or not,” says Koopowitz, “Southern California must move toward xerophytic (drought-tolerant) landscaping techniques, and these plants are ideal because they give seasonal color with minimum water requirements.”
Some of the bulbs are available commercially from catalogues (like BioQuest International, P.O. Box 5752, Santa Barbara 93150-5752) or at nurseries such as Burkhard’s in Pasadena. But most are very difficult to locate and almost impossible to see in bloom.
The UCI Arboretum Open House today, from 10 a.m. to 2 p.m., will feature a limited sale of potted plants. (Bulbs are sold at the arboretum summer sale Aug. 11.) Visitors to today’s wildflower display will also be treated to a California wine tasting and an art exhibit. Admission is $3.
If you cannot attend today’s open house but wish to support this collection and learn about drought-tolerant plants, join the Friends of UCI Arboretum (Irvine 92717, $25).
