Elephant bush

Identification and origin

Portulacaria afra belongs to the family Didiereaceae. It was formerly placed in the purslane family, Portulacaceae. It grows on rocky outcrops and slopes in southern Africa, from the Little Karoo and the Eastern Cape north to KwaZulu-Natal, Eswatini, northeastern South Africa and Mozambique, and as far as northwestern Kenya.

It is a densely branched, semi-evergreen succulent shrub or small tree. The fleshy, nearly stalkless leaves are round to oval, set in opposite pairs, glossy emerald green and only 1–1 in long. Young stems are brittle, fleshy and reddish, turning gray as they mature. In the wild the plant reaches 8–15 ft. In cultivation it stays much smaller, from 12 in for dwarf forms to about 4 ft, and it grows slowly.

It is often mistaken for jade plant (Crassula ovata), but the two are not related: elephant bush has much smaller leaves set closer together on thinner stems. The tiny pink or white flowers are star-shaped with five petals and appear in clusters at the branch tips in late spring or early summer in its native range. They are rare in cultivation, except on plants grown in the ground in mild climates. The sour-tasting leaves are eaten in southern Africa in salads and soups, and elephants and tortoises browse it eagerly.

Light

Light is the key to success. The best spot indoors is a south-facing window; east or west exposures also work. Aim for at least six hours of strong light a day. In shade the stems stretch and weaken and the leaves turn pale. If natural light falls short, a grow light set 6–12 in above the plant and left on fourteen to sixteen hours a day makes up the difference.

Very strong sun can redden or burn the leaf tips. If the plant spends summer outdoors, acclimate it gradually, or the leaves will sunburn. Variegated forms handle intense sun less well. When it comes back inside, it can drop a few leaves if it gets less light there.

Watering

Although it is very drought tolerant, it grows faster and fuller with enough water during the warm season. Water thoroughly until water runs out of the drainage holes, empty the saucer after a few minutes, then let the mix dry before watering again: as long as the top 1 in is still damp, wait. Avoid repeated light, shallow sprinklings.

From mid-spring to mid-fall the plant uses more water. In winter, cut back sharply: unless the room is unusually bright and warm, wait until the lower leaves begin to shrivel, which can take several months. Resume watering cautiously as the days lengthen.

Wrinkled lower leaves point to a lack of water; yellow leaves and softening stems point more often to excess. The dry air of most homes does not bother it, and misting is unnecessary.

Potting mix

Use a cactus and succulent mix, or a blend of roughly one-third organic material to two-thirds mineral material (fine gravel, perlite, pumice, coarse sand). Keep fine sand to a minimum, since it clogs the pore spaces. The pot needs large drainage holes; a layer of gravel in the bottom is no substitute. Unglazed clay is ideal. Because the plant is top-heavy, a rock or stake can steady it until it is well rooted.

During active growth, feed about once a month with fertilizer diluted to half strength, a little more often if you prune heavily. Avoid high-nitrogen fertilizers and do not feed in winter.

Temperature

It does well in most homes at around 61–75 °F by day, with noticeably cooler nights: night temperatures between 39 °F and 61 °F are well tolerated, especially in winter when the plant is kept nearly dry.

It can spend the warm season outdoors once all danger of frost has passed; bring it back in when nights drop below 39 °F. It does not tolerate frost. In the ground it is grown in USDA zones 9 to 11, in a sheltered spot.

Repotting

It prefers a snug pot, where the mix dries quickly. Repot when roots have filled the container or are growing out of the drainage holes, moving to a pot only slightly larger. Handle it gently, since the stems break easily. Water lightly after repotting.

Pruning

Pruning is not essential, but the plant takes it very well: it sprouts new buds wherever a branch, or even a leaf, is removed. Pinch or cut just above a pair of leaves to keep it at the size you want. Left unpruned, its stiff branches grow into a thicket, and heavy limbs can snap off.

Its dense branching makes it a favorite for bonsai. Common selections include ‘Variegata’ and ‘Foliis Variegatus’, with variegated leaves; ‘Medio-picta’, with whitish centers and bright red stems; ‘Aurea’, with new leaves that turn bright yellow in sun; ‘Prostrata’, a low, trailing form; ‘Cork Bark’, with corky bark; and ‘Limpopo’, with larger leaves. Variegated forms tend to be smaller and less robust.

Propagation

Stem cuttings are the easiest method. In spring or summer, take a stem, let the cut end dry and callus for about two days, then insert it in barely moist mix, ideally with bottom heat. Water sparingly: roots form in four to six weeks in warm conditions. Cuttings also root in water, and even leaves knocked off during pruning can root on their own.

Seed is possible but rarely used: in the wild the seeds germinate with great difficulty, and the plant spreads mostly through broken branches that take root.

Common problems

• Yellow leaves, soft stems, rot at the base: overwatering, a mix that stays too dense, or a pot without drainage.
• Wrinkled lower leaves: a long dry spell.
• Long, weak stems and pale leaves: not enough light.
• Brown patches or reddened tips: sunburn after an abrupt move into stronger light.
• Leaf drop after coming indoors: less light than outside.
• Mealybugs and scale: especially indoors. Remove them with a cotton swab dipped in alcohol. The plant does not tolerate some pesticide sprays, especially petroleum-based products: always test on a few leaves first.

The same symptom can have several causes: always check light, moisture in the mix, temperature and the condition of the roots together.

Toxicity

No toxicity has been reported for dogs, cats or people, and the leaves are eaten in southern Africa. Do not confuse it with jade plant, which is toxic to dogs, cats and horses. If a large amount is eaten or unusual symptoms appear, contact a veterinarian or a physician.