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.
South Africa is famous in botanical circles for its abundance of plants with "window" leaves. The "windows" are actually patches of translucent material on their surfaces, which transmit light to the leaf's interior.
This trait is especially useful when a plant is partly buried, and the windows admit sunlight needed for photosynthesis. Interestingly, this unusual adaptation is found in several South African plant groups, notably the ice plant family and in the genus Haworthia.
Ice plants are common in California, but Haworthias are less so. Small plants with succulent leaves, they are included in the Asphodel family, along with Aloe. Nearly all species come from South Africa, and the exceptions are found in adjacent countries.
The leaves of one widely grown Haworthia group, the "retuse Haworthias," are flattened at the ends with the translucent part at ground level and the rest of the leaf buried. Other kinds have above-ground leaves with streaks of translucence toward their tips.
The advantage of the windows is twofold: First, if the leaves are pressed closely together, the windows allow light to reach the ones sandwiched between their neighbors. Second, these little plants frequently grow beneath bushes, where leaf litter and grit accumulate. Once again, the windows admit light to the covered portions.
Haworthia cooperi, a native to the eastern part of South Africa's southern coast, can be found along a strip about 300 miles long in the Eastern Cape province. Some single plants exist, but they form clumps most often. All forms have translucent streaks toward the tips of the leaves, but some have shorter blunter leaves, while the leaves of others taper to a point. Some forms also have tiny teeth along the leaf edge.
Haworthia cooperi flowers mainly in spring, but our clump at the Ruth Bancroft Garden puts out tiny stalks all winter long as well. Each stalk bears tiny white tubular flowers, flaring at the mouth, with little reddish stripes. The flowers are neither numerous nor colorful, but nonetheless they have a certain charm.
Like other types of Haworthia, H. cooperi needs some protection from full afternoon sun, but otherwise, it is easy to grow.
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