The genus Crassula is one of the most diverse succulent genera, varying from tiny moss-like annual plants to 2m tall succulent trees like Crassula ovata. Belonging to the Crassulaceae family, there are more than 300 Crassula species of which approx. 150 are found in southern Africa, where they are widespread but concentrated in the semi-arid winter-rainfall areas. The centre of distribution of this genus is in southern Africa, but they extend beyond Africa into Europe, America, Australia, New Zealand and the southern islands. The name Crassula is the diminutive of the Latin crassus which means thick or fat, referring to the fleshy nature of the genus as a whole. This popular genus offers an extensive array of sizes, growing forms and textures making them perfect for landscaping, rockeries, windowsill plants or to be grown in containers. They can also be grown indoors as house plants. Those that make excellent house plants are the glossy leaf varieties. Crassulas, given a rich, well-drained medium will grow fast and luxuriantly.

Crassula tomentosa, commonly known as Woolly Crassula, is a perennial or biennial clump forming succulent, forming compact rosettes of greyish green, hairy leaves. Crassula tomentosa flowers early to mid-summer producing white to yellowish flowers on erect flower stems up to 60cm tall. It is monocarpic meaning that its individual rosettes flower only once in their life, set seeds and die and then replaced by new rosettes. Crassula tomentosa is a very variable species with many slightly different forms. They are somewhat hardy, tolerating temperatures as low as negative 3.9 °C.