GARDENING : Arboretum Is Rare to Go for Yearly Exotic Bulb Sale

Watsonia, ixia, sparaxis and babiana are just a few of the exotic sounding flowering plants native to South Africa that thrive, with proper culture, here in Orange County.

It’s fortunate that they do grow well in areas other than South Africa, for many of the species are considered rare and endangered in their native habitat.

One of the largest collections of these endangered South African bulbous plants is at the UC Irvine Arboretum and Gene Bank. Since 1976, under the leadership of Harold Koopowitz, the arboretum has been collecting and storing endangered plants. It was one of the first institutions to establish a gene bank and has the world’s largest collection of South African bulbs outside of that country.

In addition to collecting and preserving these endangered plants, breeding experiments and hybridization efforts are also underway.

Hybrids of some of these plants, like the highly fragrant freesias, are already finding their place in many gardens. Hybrids of babiana (baboon flower), with their spikes of freesia-like flowers in blue, lavender, red, cream and white, are also increasing in popularity.

Tall watsonia hybrids with reed-like foliage and flower spikes in flame orange, red or pink tones are also colorful in a winter garden.

One of the outstanding characteristics of these South African species is that they bloom in winter here, and add bright color at a time when gardens may lack considerable color.

The bulbs are dormant in summer, and now is the time to purchase and plant them.

The UCI Arboretum will hold its annual sale Aug. 8. The arboretum is located at the corner of Jamboree Road and Campus Drive. Doors open at 10 a.m., and the sale continues until 2 p.m. Arrive early because those in the know come from as far away as Santa Barbara and San Diego for the opportunity to purchase these rare and exotic bulbs.

Koopowitz and his staff of volunteers have collected and packaged more than 10,000 bulbs of more than 100 different species of South African bulbous plants. The packages will contain from one to a dozen, depending on the plant’s size and rarity. Prices range from $1 to $10 per bulb.

Photographs will be available for purchasers to get a better idea of what the flowers will look like when they bloom.

Some of the species are very rare and not known to the general gardening public. But they are worth a place in a private garden. “ Lachenalia mathewsii is a very rare and endangered plant that multiplies profusely in our climate,” Koopowitz said. “The small plant grows to only nine inches and produces bright yellow flowers.”

Koopowitz also recommended watsonia altedroides, a species of watsonia that performs well both in the garden and as a cut flower.

Gardeners who like the unusual may want to add ferraria to their collection.

“This is a fun and strange plant that produces star-shaped flowers, one to two inches in diameter,” Koopowitz said. “The colors range from black, brown to lavender, and the fragrance can be enticing like mint, or chocolate, or smell unpleasant. Unfortunately, you can’t know what the fragrance is until you smell the flower.”

Various species of gladiolus will be included in the sale, but not the European hybrids.

“There are now more than 200 varieties of gladiolus, and they all originate from six species, mostly from South Africa,” Koopowitz explained.

Several species of these rare plants will be included in the sale. Gladioli gracilis is one that is fragrant, but only to those people who have the genetic ability to detect the scent, which is comparable to freesia. This winter-blooming plant produces sky-blue flowers that hang on the spike like bells.

Gladioli liliaceoaus is another species that Koopowitz recommends. The plants produce trumpet-shaped flowers with a color range from yellow to brick red. At night, the flowers change color to lavender-pink and become fragrant. But the scent is no longer detectable in the daylight and the flower changes back to its original color.

“This is a situation of the plant adapting to attract its pollinating insect, a type of hover moth, by releasing fragrance at night and changing hue to attract the moth,” Koopowitz explained.

Since only two or three florets open at a time on the flower spike, and last several days, the fascinating flower display can last up to three weeks. This is the first time bulbs of this plant are being offered for sale.

While most gardeners regard oxalis as nuisance weeds, some garden connoisseurs collect ornamental oxalis. Various species in different colors will also be sold. One species has yellow flowers highlighted with red veins. Another produces lavender-pink flowers.

For information about the bulb sale, call the UCI Arboretum at (714) 856-5833.