The cotyledons are popular houseplants. These succulents are members of the Crassula family. They’re mostly native to Africa, particularly South Africa, and Arabia. These were first introduced to Europe around 1690.
These species can also be grown outdoors in warmer regions of the country. In the past some have been used as annual bedding plants.
The name cotyledon comes from the Greek meaning cup, which refers to the cup-like foliage. This name was also used by Pliny.
The growth habit of the cotyledons can vary slightly from one species to another. Some are more erect. Typically, the foliage often forms rosettes. In many cases, they resemble the hen-and-chicks.
The cotyledons have thick, stiff, fleshy foliage. In some species, it is alternate. In others it is opposite. The appearance of the leaves can vary greatly from one species to another. The edges can be entire, toothed, or even wavy. The leaf size can also vary as well. The stems are also thick and fleshy.
The flowers of the cotyledons can assume various shapes, including urn-like and tubular. These have five petals. The blossoms open on small flower scapes that have leafy bracts. These flowers can be nodding. They come in bright vivid colors, including orange, yellow, and red. These open in terminal clusters and are tightly packed together. These appear from late summer through the fall months.
These plants are very easy to propagate. Several methods are used, including different vegetative means. They’re very easy to grow from stem cuttings that can be taken after the plant finishes blooming. Leaves can also be used to propagate the cotyledons. The leaves can take three or more weeks to form roots.
So far as care is concerned, these plants need a well drained cactus-type potting soil. Though they’re succulents, they typically need some protection from the afternoon sun when they’re grown outdoors.
When the plants are actively growing, they should be watered moderately. Water carefully so that the liquid doesn’t touch the leaves. The plants need to be kept perfectly dry during the winter months.
Silver crown (Cotyledon undulata) is a particularly attractive species. This has stiff, fleshy, branching stems. The large leaves, which can reach two inches in length, are wedge-shaped. Oppositely arranged, these have wavy edges, and are up to three inches across. Over the surface of the leaves one can see numerous colors, including silver and white on a whitish-gray background. The margins are often pure white. The blooms, which open in the summer, can be orange or red.