Walnut Creek's Ruth Bancroft is a national authority on drought-resistant gardening. Twice a month, she and her staff share their knowledge with readers.
The succulent members of the ice plant family (Aizoaceae) include a wealth of interesting and unusual plants. Considering how large and diverse this group is in terms of number of species (far more than 1,000 species grouped into about 125 genera), it is remarkable how concentrated they are geographically, with the great majority native to southern Africa. Within this region, however, they are very widespread, occurring in various habitats in both the winter-rainfall and summer-rainfall areas.
As with other plant groups (Eucalyptus and Oxalis are other notable examples), the reputation of ice plants has been unfairly stigmatized by the bad behavior of a few invasive species. The rampant spread of Carpobrotus along the coast of California serves as a cautionary tale about being careful about what gets introduced into the landscape. By contrast, many of the other family members are delicate little botanical jewels that prove difficult to keep going without skilled care; these could never mount an invasion.
At Walnut Creek's Ruth Bancroft Garden, one of our missions is to try out new kinds of plants with low water requirements, with the aim of increasing the palette of choices available to gardeners in our area. The ice plant family offers many delightful prospects, many of which have not found their way into horticulture here. Avoiding the kinds that might spread aggressively, and also those too fussy to keep alive without controlled conditions in a greenhouse, we still have an astounding array of plants with which to experiment. One group that has caught our interest in the last few years is Cheiridopsis.
The 33 species of Cheiridopsis are found in the winter-rainfall region in western South Africa and adjacent southwestern Namibia. They are clump-forming, stemless plants with generally fingerlike leaves, sometimes long and slender and at other times short and stubby. All have showy flowers, usually produced in winter or spring.
We have planted several species in the last couple of years, and the first of these to come into its own is Cheiridopsis denticulata, from northwestern South Africa. It has blue-gray leaves, which are up to 4 ½ inches long but are usually shorter. These are more or less cylindrical, but with a keel extending partway down the underside. Occasionally, a leaf is produced in which the keel flares out and sports little teeth.
Our plants endured this year's bout of freezing weather without any problems, and one burst into bloom toward the end of January. The flower color in this species varies from pale yellow to white, often with a tinge of orange or pink. Our plant's huge flowers (3 ½ inches or more across) opened almost white, but with a tinge of pale yellow-orange. As with many ice plants, the flowers open only on sunny days, closing at night.
We hope other members of this delightful genus will flower in their turn and prove to be suitable as garden subjects in this area.
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