|Ice plants break the color barrier
At first, I only put one hardy ice plant in my database: Delosperma cooperi. The common name of this tough succulent comes from transparent bladders cells on the plant's surface, which hold water, creating a glistening effect. Leaves shaped somewhere between needle and jellybean grow two to six inches high, in a tight mat. With roots dense too, Delosperma crowds out other plants.
Native to eastern South Africa, Kenya, Ethiopia, and southwestern Arabia, these plants love sandy, poor soil; tolerate drought; and demand full sun in order to put out their short, shiny daisies. Around here they die back in winter preceded in fall with some of the red the leaves turn in warm-winter zones.
D. cooperi sports magenta flowers, mid-May till frost. In 2003 I recorded similar Delosperma floribundum, with two-tone petals lilac on the outside, and white around the small yellow eye.
But with my prejudice against warm colors, I didn't note golden yellow to orange-red D. nubigenum, which comes from higher elevations, and so is even hardier. Lower growing, too, and blooming only in spring but just as tight and dense: an excellent groundcover. Or D. congestum, a clear yellow, only half an inch tall, a true alpine from the highest mountains of the region. This one needs a bit more moisture, but grows just as dense.
Or perhaps these were not available till recently? My 1094-page reference book, the American Horticultural Society A-Z Encyclopedia of Garden Plants, published in 1997, doesn't mention any hardy ice plants only annuals. On a Web page dated 2004, Gerhard F. Wagner, president of the German Society for the Other Succulents, complains of confusion in both identification and classification of Delosperma. Clearly there's a wealth of these plants not widely available even now. ("Other succulents?" Besides cactus, that is.)
Confusion? Sometimes instead of Delosperma, the genus is called Mesembryanthemum. The United States Department of Agriculture classifies it in the family Aizoaceae; the South African National Biodiversity Institute, in Mesembryanthemaceae. In the family, several genera are called "ice plant."
Now I'm captivated by Delosperma "Kelaidis," named after Panayoti Kelaidis, Curator of Plant Collections at the Denver Botanic Gardens, where the plant was discovered in 1998 apparently a volunteer hybrid of D. cooperi and D. nubigenum. Mostly quite similar to D. cooperi, "Kelaidis" (also known by the trademark name "Mesa Verde") blooms in a unique shimmering peach that has melted my resistance to warm colors.