Crassula is a genus of about 200 species of annual and perennial succulent plants. As a type of cactus plant, it belongs to the family Crassulaceae, otherwise known as the stonecrop or orpine family. These plants are typically found in in Asia, Madagascar, and Africa. The most cultivated varieties originated in the eastern cape of South Africa.
This group of succulent plants varies greatly in size, shape, and color. Normally they have thick, fleshy leaves with yellow, white, or red flowers that range from less than 1 inch (2.5 cm) to 6 feet (1.8 m) in height. The leaves of some varieties have a tubular shape, while others are flatter and curled.
Stem or leaf cutting is the typical method by which Crassula plants are propagated. When propagating the plants, which is best done during the spring or summer, the cuttings are usually dried for several days. The cuttings are inserted only as deep as required to hold them in place.
While the plants in this genus tolerate different light intensities, the species require direct sunlight in order to acquire the dense growth and leaf coloration similar to that of wild plants. Extreme heat or cold can cause these types of plants to lose their foliage and die. A small degree of frost can be tolerated by some of the cultivated varieties, however. Over-watering stimulates root production but also causes rotting in the lower stems.
One popular plant in this genus is Crassula ovata, also known as the jade plant, lucky plant, or money plant. With small white or pink flowers, it is commonly used as a houseplant all over the world. Its branches are thick and smooth with leaves that grow in pairs opposite each other. The color of the leaves is a jade green, with some varieties exhibiting a red tinge on the edges when exposed to strong sunlight. This plant can be used in the art of bonsai and is popular among those who practice it.
The usual pests for plants in the Crassula genus are mealybugs, which can cause deformation in new growth. A cotton swab or paintbrush dipped in rubbing alcohol can be used to kill the infestation. Aphids are also considered common pests, even though they typically attack only the flower stalks of these plants. These types of plants are generally intolerant of older pesticides, although some people have used modern systemic insecticides with no adverse effects.