Euphorbia horrida mostruosa


Euphorbia polygona var. alba
Euphorbia polygona var. horrida


E. horrida is native to South Africa: Cape Province and Eastern Cape. The forma mostruosa is a natural mutation that occurred in the E. Horrida population and that was selected and propagated vegetatively.


E. horrida is a succulent of the Euphorbiacee botanical family. The plant has a shrubby habit and tends to form clumps of stems. Stems are bright green and consist of a variable number of ribs. Ribs are arranged in tubercles with flat edge, and these bear short brownish spines. The succulent grows in a disorderly way and the normal form can reach up to 75 cm in height, but the mostruosa form is very reduced in size. Spines are 2,5 cm long and are rigid and manly located on the upper part of tubercle but not on the tips. During the spring-summer period, the plant blooms producing on the apex of the stem some green yellow Ciathya. Ciathya are the typical inflorescence of the Euphorbia, it is an inflorescence consisting of a cuplike cluster of modified leaves enclosing unisexual flowers. The forma mostruosa instead, does not produce flowers because its mutation. When the flower stalk dries up, a spine forms.


This is a slow growing succulent but quite easy to cultivate. For this succulent the best sun-exposure is full sunlight, and the plant does not like temperatures below -4 °C so it needed to be placed indoors. The soil should be mixed with pumice, clay and loam to allow the drainage and prevent the root rot, the plant is prone to it indeed. Remember to use perforating pot to drain excess water. Watering can be done regularly from March to November: during the vegetative period you can water the plant (every 7 days), checking that the soil is completely dry before watering again; in winter you should stop the watering to allow to the plant to enter dormancy. If you want a very fast and lush growth you can fertilize the plant once a month during the growing season with the specifics fertilizers for cacti; stop fertilizing throughout the winter. The pot should be quite large and deep because the root is large and tuberose. 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. Handle the plant carefully and wear gloves because the latex it exudes is toxic.


Propagation can be done only by cutting, to not lose the mutation of the forma mostruosa. By cutting you can use the offsets that grow at the base of the plant. Cut the offset as close as possible to the base of the stem 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.


Species of the Euphorbiacee family normally if are damaged, exude a white milky sap, called latex. Many plants produce latex, but in the Euphorbiacee this latex is often poisonous and may irritate skin. The poisonousness is due to some alkaloids so it is best to keep the plants away from children or pets.

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