Cacti & Euphorbias

Among the first changes Madame Ganna Walska made after purchasing Lotusland in 1941 was to add cactus, succulent, and euphorbia plantings to beds in front of her new residence, relying on the help of respected landscape architect, Lockwood de Forest. These plantings reflect both Ganna’s design style and her fascination with desert plants. Serving as teacher and advisor to a woman who had no horticultural knowledge but knew the visual effect she wanted to achieve, de Forest soon became a willing collaborator in carrying out her ideas. Initially hesitant to have cactus in front of the house, he later exclaimed, “You are wonderful! I never would have thought of using cactus at the front door, or many of the other plantings you suggested. They are very handsome and I congratulate you.”

Convergent Evolution: Looking down the main drive from the house, it may at first appear that there are cacti on both sides of the trail. In actuality, the left side of the drive is planted with cacti, which are New World plants from the Americas, while the right side is planted with Old World euphorbias, mainly from Africa and Madagascar. Despite their similar appearances, these two families of plants are not related! Rather, they provide an excellent example of convergent evolution, meaning they fill the same ecological niche in similar climates on opposite sides of the world. Many cacti and euphorbias converged upon the same adaptations, particularly spines, shallow root systems, and succulent stems for water storage.

Golden barrel cactus (Echinocactus grusonii): The golden barrel cactus takes fifteen years to bloom, sprouting small yellow flowers that are pollinated mostly by bees. They are some of the most widely cultivated cacti in the world, yet were previously considered almost extinct in the wild with as few as fifty plants remaining, until a second population was discovered in 2005. This population is 500 km away from the original and contains over 10,000 plants, therefore the species was downgraded by the from critically endangered to endangered. One of her favorite plants, these cacti are a good example of Ganna’s penchant for mass plantings, a signature of her style.

Euphorbia ingens: Among the succulent species in the genus Euphorbia, there are a few that attain tree-like stature. Euphorbia ingens is probably the most well-known outside of Africa. Because it actually grows into a tree that may be as tall as 40 feet, it has a woody trunk that is used as timber in some parts of South Africa. Lotusland has both the normal, upright form and the weeping form of E. ingens. The reason for this weeping form is unknown, but it is believed that a genetic variation leads to this distorted effect.

Oreocereus celsianusAlso known as ‘Old Man of the Andes’ or ‘Old Man of the Mountain’ this entertaining cactus has coarse, white hairs to protect it from the intense ultraviolet light of its high altitude native habitats. Originating from the Andes Mountains, O. celsianus is a frost, hardy ornamental and will provide large, red tubular flowers in the spring.

Notable species: Euphorbia caput-medusae (Medusa’s Head Euphorbia), Euphorbia horridaEuphorbia resiniferaParodia leninghausii, Parodia magnifica, Neobuxbaumia polylopha.