Rukam

Photo: Michael Hermann — CC BY-SA 3.0 · source

Survives zone 9 and warmer

Winter protection required

Harvest calendar

Ripens: Warm-season flushes, heaviest in the wet season

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Sweet-tart, plum-like fruit with firm flesh and skin, eaten fresh once fully colored or preserved. Root suckers make it possible to propagate spineless individuals vegetatively, sidestepping the thorny branches typical of a seed-grown tree. Its cold hardiness is genuinely unsettled — some sources rate it zone 9-11, others 10-12 — so treat zone 9 here as the more optimistic reading rather than a confident rating, and expect it to need real winter protection at that edge.

Hardiness

Zone 9+

Habit

Tree

Edible part

Fruit

Ripens

Warm-season flushes, heaviest in the wet season

Mature size

To about 10–15 m in the wild, smaller under cultivation

Light

Full sun to part shade

Soil pH

5.5–7.0

Environment

Humid tropical to lower montane forest

Native range

Island Southeast Asia and Melanesia, spread into mainland Southeast Asia, India and Polynesia — humid tropical forest from sea level to 1,500 m, occasionally found wild to 2,100 m.

Status

Both wild and cultivated

Years to fruit

2–3 yrs

Growth speed

Moderate to fast

Spacing

600 cm (236 in) apart — about 36 m² (388 sq ft) per plant

Leaf shape

Glossy, on branches that are thorny in seed-grown trees, spineless in some selections

Root system

Spreading and strongly suckering — and the suckers are the practical point, since they are how a spineless selection is propagated. Seedlings come up thorny; a sucker off a spineless tree does not.

Fruit description

Rounded, about 2 cm, green to pink, purplish or dark red; firm, richly flavored sweet-tart flesh

Propagation

Seed (germinates readily), or root suckers for vegetative propagation of spineless selections.

Pollination

Insect-pollinated, and dioecious in the main — male and female flowers are usually on separate trees, so a female needs a male nearby, though occasional trees carry both.

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.