This sweeping collection of cactus was donated to Lotusland by a longtime friend of Madame Walska, Merritt Dunlap. Beginning his collection in 1929, Dunlap grew approximately 40 percent of the plants from seed. The move from Dunlap’s home in San Diego to Lotusland was a sight to behold: Stake-sided trucks with hundreds of towering cacti rolling down the highway, the largest with wooden boxes constructed around their excavated roots and wooden crates to hold their branches together. Five hundred thirty plants across three hundred taxa were moved, each with meticulous records of their orientation to the sun for replanting. When cacti are relocated it is important to maintain the same orientation they had before because the southern facing side of cacti becomes toughened in the sun, while the north side is susceptible to sunburn. Three hundred tons of sun-soaking diorite, an igneous rock (meaning it is from magma) were used to create the beds, and stunning formations of igneous basalt add drama to the entrance. The garden opened to the public in 2003. Today, it contains more than 300 species of cacti grouped by their country of origin.
Ants and Cactus:
There’s a strong interdependence between ants and cactus. Many species of cactus attract ants with extrafloral nectaries, nectar secretions that are not in a flower but rather right on the stem of the cactus. While this provides obvious benefits to the ants in the form of food, it also provides benefits to the cactus because it inspires the all-mighty ants to take an interest in protecting their food source. The ants use their hive-minded nature to fight off other predators and invaders. As you walk the cactus garden, look for the ants and see if they lead you to these extrafloral nectaries!
Galapagos Opuntia (Opuntia galapageia):
On the Galapagos Island, giant tortoises and iguanas rely on cacti as a primary food source. Some Galapagos cacti including this Opuntia galapageia have developed a fascinating way to avoid over predation, by growing into massive tree-like proportions. Tortoises must wait for fruits and pads to fall. Yet, it is an arms race of evolution. In some parts of the Galapagos, tortoises have evolved special shell shapes that allow them to be able to stretch up higher.
Totem Pole Cactus (Pachycereus Schottii Monstrosus):
If your image of a cactus always includes spines, then think again. The monstrosus variation of Pachycereus Schotti is completely spineless, the result of a naturally occurring mutation. Mutations, changes within DNA, are the building blocks of evolution. In the absence of spines, the areoles, small bumps that would otherwise hold the spines, create the appearance of faces etched into it, and giving this cactus the common name “Totem Pole Cactus.”
Creeping Devil cactus (Stenocereus eruca):
It is easy to see how this low lying cactus got its name. If the creeping devil appears to be in snakelike motion, that’s because it actually is. While most species of cactus grow vertically, toward the sky, the creeping devil grows flat on the ground with a slightly raised tip. As it grows the underside of the stem starts to grow roots toward the plant’s tip. The rear end dies, decaying into the soil providing nutrition for continued stem growth.
Notable species: Opuntia endemic to the Galapagos Islands; several blue, sculptural species of Armatocereus from Peru; and a complete collection of the genus Weberbauerocereus. Dry-growing bromeliads, and several Agave species provide contrast and interest.