Coffea canephora aka Congo Coffeetree

Coffea canephora, or robusta coffee, belongs to the Rubiaceae family. Its native range runs from western tropical Africa to South Sudan and northern Angola. It grows in the wet tropics, including rainforests and forest edges. People grow this evergreen shrub or small tree for coffee. The name Coffea robusta is a synonym of this species.

Garden plants reach about 13–26 feet [4–8 metres] tall. Their spread reaches about 5–8 feet [1.5–2.5 metres]. Larger plants can reach 39 feet [12 metres]. The shape varies, from upright growth to a broad, umbrella-like crown. Glossy, dark green leaves grow in opposite pairs. The RHS gives a maturity time of five to ten years.

White flowers appear in summer, where leaves meet the stems. Each flower has five petals and a sweet scent. Green fruits follow, then turn red over several months. These red fruits are often called cherries. Each holds two seeds, the familiar coffee beans. Growers can raise plants from fresh seed, though sprouting can be uneven.

Give plants partial shade and moist soil that drains well. Loam with added organic matter suits them. The soil can be acid or neutral. Under glass, use a peat-free, loam-based potting mix. Keep humidity moderate to high, and shield plants from draughts. Water freely while growth is active, but reduce watering in winter. Feed every two weeks during the growing season. Repot in spring every two or three years. The RHS rates it H1A, needing glasshouse warmth above 15°C all year. Useful Tropical Plants warns that temperatures of 5°C or below can kill it.

In cool climates, it suits a warm greenhouse, conservatory, or indoor space. Its leaves, scented flowers, and red fruit offer year-round interest. Plants may need pruning to limit their size under glass. Watch for glasshouse red spider mite. The RHS also lists it as a high-risk host for Xylella fastidiosa. Seeds supply coffee blends and instant coffee. Some traditions boil unripe whole fruits with herbs before drying and chewing them. Caffeine in the seeds acts as a stimulant. Useful Tropical Plants lists no known hazards, but also notes an allergenic seed compound. That report does not establish safety for pets. Fruit pulp and the seed coverings can serve as mulch or manure.