Crassula rupestris ‘High Voltage’


Purgosea rupestris


Crassula rupestris is native to Cape Provinces and Namibia, the cultivar ‘High Voltage’ has garden origin.


Crassula rupestris ‘High Voltage’ is an uncommon cultivar belonging to the Crassulaceae botanical family. The stem is short and erect and the plant tends to branch from the base. The succulent is very small and can reach up to 8 cm in height and 5 cm in diameter. The leaves are sessile, directly inserted on the stem, very close each other and form small rosettes. The leaves are triangular, rounded, fleshy, arranged in opposite pairs, they are grey-green to yellowish-green in color and can take reddish hues on the margins if exposed to the sunlight. Blooming occurs from the early spring to the late summer and the blossoms are borne at the apex of the stem. The flowers are borne in clusters they are numerous, small, star-shaped and the color range from white to pink.


The plant has a slow growth rate but it easy to cultivate. The best sun-exposure is in bright place but is recommended to avoid direct sun-light in the hottest periods. Long exposure to direct sun-light can cause burns and burnt spots. The minimum temperatures that the plant can withstand are 7° C, below this temperature it begins to suffer and going down further it no longer survives. Too low temperatures can cause the stem or leaves to break due to water freezing inside the tissues. Temperatures between 10 and 15 °C allow the plants to enter vegetative rest which is essential for the flowering of the following year. Plants should not be placed inside the house where average temperatures of 20 degrees prevent vegetative rest. The best draining soil for this genus is made up of 33% fertile loam, 33% pumice and 33% coarse sand. The pumice should always be placed on the bottom of the pot. Remember to use a perforating pot to drain excess water. Watering can be done regularly during the vegetative period. During the vegetative period you can water the plant every 5 days with half a glass of water, checking that the soil is completely dry before watering again; in winter you should stop the watering to allow the plant to enter dormancy. Decrease the amount of water if the plant is kept indoors or if the pot is smaller than 12 cm. The plant is used to growing in poor soils, for this reason it does not need abundant fertilization, it is sufficient to fertilize once in spring and once in summer. If the pot starts to be too small for the plant you can repot the plant in a pot 2 cm wider. Repotting should be done early in the growing season with fresh new potting soil; it is usually done every 3-4 years. Be careful to red spiders and mealy bugs.


Propagation is usually done by leaf cutting or by offsets. For leaf cutting you can cut some healthy leaves and plant it in a pot with sand and loam. Place the pot in a warm and bright environment and in 1-2 months the cuttings will be ready to plant. By cutting you can also use the offsets during the spring. Cut an offset and then let it dry; after a few days the cut surface will dry and a callus will form, then place the cutting in a mixture of sand, soil and pumice. To increase the success of propagation you can make two or more cuttings at the same time. It is advisable to use rooting hormone at the base of the cut to energize root development. For cuttings it is recommended temperatures around 20 °C.


From its name you could say that it is the “succulent plant” par excellence: its name comes from the Latin crassus, that means fat. The Crassula is a plant unpretentious but with a high vegetative strength: for this reason, it is sometimes used in a closed area for air purification, which is filtered by eliminating harmful substances. The specific epithet “Rupestris” derives from Latin and means “rocky” or “found on rocks”, in fact, in nature it grows among the rocks of the Orange River in the Fish River valley

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