Ardisia crispa aka Japanese Holly

Ardisia crispa, or Christmas berry, is a shrub that stays green all year. It is part of the primrose family, Primulaceae. Its native range starts in the eastern Himalaya. It runs into China and Indochina. The plant also grows in temperate East Asia, including Japan and Taiwan. In the wild, it grows in forests and bamboo woods. It also grows in valleys and damp sites. Records range from low hills to higher mountain slopes.

This shrub has a compact, bushy shape and dark green leaves. The leaves are oval to oblong. Their edges are crenate, with small, rounded teeth. The RHS says plants reach about 4 feet [1.2 metres], often less. Its size guide allows up to 5 feet [1.5 metres]. Full-grown plants spread about 1.6–3.3 feet [0.5–1 metre]. They take five to ten years to reach full size. Small, pinkish flowers grow in panicles, or branched flower groups. Red berries follow and stay on the plant for months. The year-round leaves and lasting fruit make it a valued garden plant.

Grow it in bright, filtered light, out of midday sun. The RHS suggests loam-based compost with no peat. Add horticultural grit to the mix. It lists neutral soil that drains well. Give plenty of water during growth, and less at other times. Feed once a month during growth with a balanced liquid fertiliser. Give plants good airflow in summer. Plants kept outdoors in summer need shelter and no frost. This suits patio pots and growing spaces that give shelter. PFAF also lists woodland gardens and shaded edges as uses.

The sources differ a lot on how much cold plants withstand. PFAF lists USDA zones 6–9; the RHS gives H2. The RHS rating means plants cannot survive a freeze. Its care guide suggests winter heat near 45°F [7°C]. Follow that winter care advice; do not assume plants withstand cold. The RHS reports few usual pest or disease problems. Sow seed in spring, with warmth near 55°F [13°C]. You can also grow plants from semi-ripe cuttings in summer.

Take care with reports on food use and safety. PFAF records raw leaves as a salad food. It gives the plant a low food-use rating. It also records folk remedies made from roots. Other recorded treatments use the plant on the body's surface. These records do not show that home treatment is safe. The RHS warns that people and pets must not eat the fruit. It also says to wear gloves and other protection when handling plants. PFAF reports no known hazards, in conflict with that warning. Treat the berries as decoration, not food.