ISI 2016-15. Kalanchoe robusta Balfour

If one has ever searched “dragon trees” on the internet, or just had the good fortune to stumble across them, or been sent a link by a well-meaning friend, one will surely be familiar with the fantastic images of groves of these otherworldly umbrella-shaped trees that dominate the landscape in parts of the Island of Socotra. Located in the Arabian Sea, slightly closer to the Horn of Africa than the Arabian Peninsula, this island belongs to Yemen. In the spotty shade provided by these natural parasols, one can find a fascinating array of other Socotran endemics. Among those is the rarely cultivated Kalanchoe robusta, the specific epithet of which refers to the plants size rather than its ease of cultivation: it forms pachycaulous specimens to half a meter tall. The author’s photograph of a flowering specimen in the Illustrated Handbook (Crassulaceae volume) is of a Lavranos collection made in 1967. That plant survived for many years at the Huntington (HBG 21118) but gradually declined after flowering and finally succumbed to rot earlier this decade. Rooted cuttings were distributed as ISI 1673 in 1986 but I suspect few if any of those persist in cultivation. Fortunately, that indefatigable Arabian explorer Tom McCoy has visited the habitat and introduced a new collection. This was initiated into tissue culture so that we can now offer vigorous plants once again. Tom found the plant growing on limestone on the Dixam Plateau on the Island of Socotra. HBG 125300, $10.

Photo © 2016 by Karen Zimmerman. Images may not be used elsewhere without permission.

Published in the Cactus and Succulent Journal, Vol. 88 (3), May-June, 2016