This is probably the most commonly grown crassula in South Africa and well-known as a container plant all over the world, both indoors and outdoors.
A large well-branched, compact, rounded, evergreen shrub 1 - 3 m tall with glossy, dark grey-green, oval, succulent leaves and rounded heads of pink flowers in winter-spring. The stem is stout and gnarled and gives the impression of great age, and its branches are also short and stubby but well-proportioned. Branches are succulent, grey-green in colour and in older specimens the bark peels in horizontal brownish strips.
The leaves are 30 -90 mm long and 18 - 40 mm wide, egg-shaped to elliptic, often with a red margin and a somewhat pointed end. They are in opposite pairs, the one pair arranged at right angles to the next, and they are clustered towards the ends of the branches. The bush is covered in masses of sweetly scented, pretty pale-pink, star-shaped flowers in tight rounded bunches during the cool winter months (June-August). The flowers develop into small capsules, each holding many tiny seeds.
Crassula ovata is very similar to Crassula arborescens. C. arborescens occurs only in the Little and Central Karoo and has a distinct waxy bloom on its leaves, and its leaves are almost spherical.
Crassula ovata is a prominent element of the Eastern Cape and KwaZulu-Natal valley thicket vegetation, together with a variety of aloes, euphorbias, Portulacaria afra and other succulents. It occurs from Willowmore to East London and northwards to Queenstown and KwaZulu-Natal where it grows on rocky hillsides.
Crassulas have a special way of reducing water loss from their leaves without limiting their ability to photosynthesise, known as Crassulacean Acid Metabolism or CAM. All plants need CO2 (carbon dioxide) for photosynthesis. Most plants take in CO2 during daylight hours through their stomata (pores in the leaves) and can't avoid losing water at the same time throught these open pores. In Crassula the stomata are closed during the day but open at night when the CO2 taken in is stored in the form of organic crassulacean acids. During the day, these acids are broken down and the CO2 released is re-used in the photosynthetic process. In this way they lose much less water yet can photosyntesise normally during the daylight hours. Furthermore, during extremely dry periods they won't even open their stomata at night, and will re-cycle the CO2 within the cells. They won't be able to grow at all but the cells will be kept healthy - this is known as CAM-idling.
In addition to being a CAM plant, and having succulent water-storing stems, leaves and swollen roots that give it the ability to survive droughts, this crassula can also survive being grazed, trodden on or knocked over, as it is able to root from any piece of stem, even a single leaf.
The flowers attract bees, wasps, flies, beetles and butterflies. The fine dust-like seed is dispersed by the wind. Tortoises love the leaves but rarely devour them completely. Any discarded leaves left around the foot of the plant send down roots and grow into new plants. The stems also make handy bases for wasps to build their nests.
Derivation of the name & historical aspects
Crassula ovata was first described in England in 1768. 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. The species name ovata means egg-shaped, referring to the leaves.
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. 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.
Uses & cultural aspects
The Khoi and other African tribes ate the roots, they were grated and cooked after which they were eaten with thick milk. The leaves were also used medicinally, boiled in milk as a remedy for diarrhoea, and used to treat epilepsy, corns and as a purgative.
In the Far East, Germany and the USA it is traditionally grown in square porcelain tubs with 'lion feet' to bring good financial luck, and has attracted more common names including the Money Tree, Penny Plant, Dollar Plant and Tree of Happiness.