Kalanchoe daigremontiana (KAL-n-QWEE day-gree-MON-TEE-ah-nah) is called Devil's Backbone because its distinctly notched edges on its lance-shaped leaves are said to resemble a spine. More often, daigremontiana answers to the nickname Mother of Millions because plantlets arise in the cradle of the leaf-edge notches. Kalanchoe daigremontiana closely resembles Kalanchoe tubiflora, which has narrow tube-shaped leaves that produce plantlets at the tips.
French botanists Raymond Hamet and Perrier de la Bathie first described daigremontiana in 1914. They dedicated the species name to Monsieur and Madame Daigremont, who were members of the French Society of Botany. Kalanchoe was an established genus name, corrupted from a Chinese common name for one species. Daigremontiana is identified in many publications as Bryophyllum daigremontiana because some authors divided the Kalanchoe genus into three sections (Kalanchoe, Bryophyllum and Kitchingia) based on minor characters of the bloom. As early as 1938, chromosome studies suggested the division was baseless, and recent DNA work confirms that.
Daigremontiana is native to southwest Madagascar, where it grows among spiny shrubs on porous soils developed over sandstone. Habitat includes Onilahy and Fiherenana river valleys, the nearby sandstone plateau of Isalo National Park, the deep canyons of Makay crystalline massif and the port of Tulear between the rivers' mouths. The region is semi-arid, with 15 inches annual rainfall. Average high temperatures are in the mid-90 degrees Fahrenheit during the November to March rainy season, which accounts for 85 percent of precipitation. The dry season high temperatures are in the upper 70s F. Half of all 144 species of Kalanchoe are native to southwest Madagascar, where DNA studies suggest Kalanchoe originated.
The leaf of daigremontiana is actually a specialized stem. The plantlets at the edges of the leaf are also specialized stems. A simple example of a specialized stem/leaf is prickly pear cactus, which assembles stem on stem on stem, each capable of falling to the ground, rooting and growing a new plant. In daigremontiana, the apical meristem (growing tip) of the stem is displaced to the edges, where growth is continued as plantlets. Each leaf can produce dozens of clones.
Allelopathy: Chemical Warfare
Daigremontiana exudes chemicals into the air and soil that inhibit the growth of its own plantlets, as well as other nearby plants. Plants such as crabgrass, millet, crimson clover (Trifolium incarnatum), lettuce, onion and chrysanthemum are known to be inhibited by daigremontiana. Corn, wheat and oats are not inhibited. In addition, toxic compounds in daigremontiana pose a threat to grazing animals.
Daigremontiana is a member of Crassulaceae, the stonecrop family. Cultivation is similar to other stonecrop succulents or to aloes. Daigremontiana grows a single stalk 3 feet tall, with 6- by 1 1/4-inch, oblong-lanceolate leaf-like stems. Leaves are medium green with purple freckles on the underside. Grow it in potting mix with 30 percent sand. Allow the soil to dry between waterings during the growing season. In winter months, little water is required. Fertilize annually.