Jade plant

Identification and origin

Crassula ovata belongs to the family Crassulaceae; it is still often sold under its old name, Crassula argentea. It is native to southeastern southern Africa, from southern Mozambique through KwaZulu-Natal to the southeastern Cape, where it grows in dense valley thicket. It has naturalized in California, the Iberian Peninsula, Madeira and the Canary Islands. The genus name comes from the Latin crassus, “thick,” for the leaves; ovata means “egg-shaped.”

It is a well-branched succulent shrub whose thick, fleshy stems eventually form a gnarled trunk, giving the plant the look of a miniature tree. New growth is green or reddish brown, and older stems turn gray. The oval, thick, glossy leaves are 1–4 in long; medium to dark green, they pick up red edges in direct sun. In the wild it reaches 6 ft; indoors it is usually 18 in – 2.5 ft tall, though an old plant can approach 5 ft. Mature plants sometimes produce rounded clusters of small, star-shaped white or pink flowers with a faint sweet scent in winter or spring; indoors, blooming is rare.

Light

It needs at least four hours of direct sun a day: a south-facing window or bright filtered light works well, with a little protection from the harshest midday sun. In too little light, stems stretch and droop, leaves stay a flat green without red edges, and the plant loses its shape. If you want flowers, count on at least six hours of strong sun. Without a suitable window, a full-spectrum grow light placed close to the plant for twelve hours a day can stand in for the sun.

Watering

Water deeply, then let the mix dry out before watering again. In spring and summer, while it is growing, the plant drinks more; from fall through late winter, water much less often, giving just enough to keep the leaves from puckering. Use room-temperature water: cold water can cause leaf drop. Let the excess drain, empty the saucer about fifteen minutes later, and avoid splashing the leaves. Puckering leaves are asking for water; leaves dropping while the stem rots mean the opposite, too much.

Potting mix

It needs a very free-draining, airy mix, such as a cactus and succulent mix with a little organic matter added. A homemade blend also works: one part potting soil, one part peat moss and three parts coarse sand. Avoid mixes that already contain fertilizer, and choose an unglazed clay pot with drainage holes, which lets the mix dry faster than plastic or glazed pots.

Temperature

It grows well at 64–75 °F by day, with cooler nights around 50–55 °F. A cool winter rest at 45–55 °F does it good; do not let it drop lower. It tolerates a wide range of temperatures and dry indoor air, but freezing kills it. Keep it away from cold windowpanes and chilly air currents in winter, and give it good air circulation. To trigger blooming, cut back on water in fall and keep it cool, around 55 °F, especially at night, in a room with no artificial light in the evening: natural long nights set the buds. It can only live outdoors year-round in USDA zones 11a to 12b.

Repotting

It is happy root-bound and can stay in the same pot for years; just replace some of the surface mix each year. Repot every two to three years, or as soon as the plant gets top-heavy and starts to tip, in spring when new growth begins. Choose a slightly larger pot that is heavy enough to keep it stable. If you keep the same pot, trim the roots lightly and cut back the stems to keep it balanced. Wait about four months before feeding a freshly repotted plant.

Pruning

Pruning keeps it compact and vigorous, thickens the trunk and lets you train it into a miniature tree or bonsai. Prune in spring: first remove damaged branches, then cut back up to a third of the growth with clean, sharp pruners, just above a node or a side branch. Pinching the tips of new shoots just above a pair of leaves makes the plant bushier.

Propagation

It is very easy to propagate from stem or leaf cuttings. Let the cutting dry for a few days so the cut end calluses, then set it on a free-draining, barely moist mix. Rooting is fastest in summer but works any time of year. It can also be grown from seed sown in spring or summer.

Common problems

The same symptom can have several causes: check light, watering and temperature before drawing conclusions.

• Mealybugs: the most common pest, showing up as white cottony tufts that distort new growth. Wipe them off with a cotton swab dipped in rubbing alcohol. Avoid insecticidal soap and be cautious with insecticides, which can damage the fleshy leaves.
• Other pests: spider mites, scale and aphids.
• Root and stem rot: caused by a mix that does not drain or by watering too often.
• Leaf drop: too much or too little water, cold water, or simply the natural aging of leaves. Leaves damaged by sunburn, a spray or cold will fall, and new ones grow back.
• Dark spots or gray-brown corky scabs: most often from soil that stays too wet, sometimes from cold, sunburn or powdery mildew.
• Tiny powdery white dots: mineral deposits from hard water or too much fertilizer.
• Stretched, drooping stems and dark green leaves without red edges: not enough light.

Toxicity

Toxic to dogs, cats and horses; the toxic compound has not been identified. After ingestion, signs can include vomiting, depression and lack of coordination. Keep the plant out of reach of pets and, if one has chewed it, call a veterinarian promptly.