Euphorbia ambovombensis

Euphorbia ambovombensis is a small succulent, a plant that stores water. It belongs to the spurge family, Euphorbiaceae. It comes from Madagascar, but sources differ on its range. Kew lists the centre of Madagascar. LLIFLE places it near Ambovombe in the south. LLIFLE says it grows beneath shrubs in Alluaudia-Didierea forest. There, it grows in deep shade on rich soil. Kew lists desert or dry shrubland as its home. Fire and clearing land for charcoal threaten its habitat. So does collecting plants.

This plant grows slowly into a low bush with upright branches. It reaches about 1.1 feet [0.35 metres] tall. Its swollen base, called a caudex, stores water. The grey-brown caudex may be round, oval, or uneven. It measures about 0.13–0.33 feet [0.04–0.10 metres] across. Thin, round stems branch chiefly near the base. Brown scars show where old leaves fell. Thick leaves with a leather-like feel spiral near branch tips. They range from green to brown and copper. Their edges curl upward and form waves. Light and water levels affect the strength of these waves.

Small flowers grow between the leaves. They draw little notice, with pale green or light brown hues. Its shape and caudex give it its main garden appeal. Growers keep it as a collector's plant or train it as bonsai. Plants grown from seed form a rounder base than cuttings. Cuttings tend to form a cluster of swollen roots instead. The caudex takes many years to grow in size. Raising it above the soil too soon stops further growth there.

This tender plant needs warmth and strong light in gardens. LLIFLE gives USDA zones 10–11. It also supports direct sun in summer. Keep light bright in winter, even when growth slows. Use a very airy mix made mostly of mineral matter. Pots need large drain holes so water can escape. Water at regular times while the plant grows. Do not let water stand around its roots. Keep it almost dry in winter. Its stored water helps it cope when growers miss watering.

Rot is a major problem, so this succulent needs great care. Cold, damp spells pose a high risk while it rests. Too much water can kill it. So can watering in the wrong season. Growth may pause as old leaves fall. At that point, new leaves stop forming. Growers can raise more plants from seed, cuttings, or grafting. Sow fresh seed soon, as stored seed loses its power to sprout. Let cut surfaces dry and heal before planting cuttings.