Clerodendrum japonicum aka Japanese Glorybower

Clerodendrum japonicum is also known as Japanese glorybower. It belongs to Lamiaceae, the mint family. This shrub sheds its leaves and grows in warm Asian regions. Sources list China, India, and much of Southeast Asia. The RHS also lists Japan in its native range. Wild plants grow among shrubs in valleys and beside streams. They also grow in grassy gaps and moist gullies. Some records place them in shade in Nepal.

The shrub grows upright and has woody stems. Garden sources give a height of about 8.2 feet [2.5 metres]. A broader account gives 3.3–13.1 feet [1–4 metres]. It sheds its leaves during its deciduous phase. Flowers grow on shoots formed in the current season. PFAF says it blooms from July to October. Seeds ripen from August through November. Each flower has both male and female organs. Insects help the flowers set seed by moving pollen. These include bees, butterflies, and moths.

Grow this shrub in sun, with shelter from cold winds. It accepts sand, loam, or clay that drains well. Rich soil with plenty of humus suits it best. The soil can be slightly acid, neutral, or slightly alkaline. Keep the soil moist through the growing season. PFAF warns against letting it dry out as it grows. The plant cannot stand much cold and needs a warm site. Useful Tropical Plants says it briefly tolerates about 27°F [−3°C]. PFAF lists USDA zones 9–11. It doubts the plant can survive outdoors in Britain.

Gardeners grow this shrub for its looks. It also helps restore native habitats as a pioneer plant. Sources differ on whether it may become a weed. PFAF says no. Useful Tropical Plants warns that it could become a weed. Growers can raise new plants from seeds or root cuttings. They can also split off suckers when the plant is dormant. Seeds may sprout unevenly and take 20–60 days. PFAF says to keep seedlings under glass for their first winter.

People gather this plant for food and traditional medicine. They cook or pickle young leaves and shoots. PFAF also lists flowers as edible but says they smell bad. Traditional uses include leaf poultices, which people place on the skin. People also make preparations from flower clusters. These records do not prove that such treatments work or are safe. Both plant-use sources say they know of no hazards. This does not mean they have proved it safe. Useful Tropical Plants reports a 2018 conservation assessment of Least Concern.