Calycanthus occidentalis aka California Spicebush

Calycanthus occidentalis belongs to the Calycanthaceae family. This shrub sheds its leaves each year. People call it California allspice or western sweetshrub. Kew places its native range in northern and central California. Other sources give a wider range. They include possible sites in Washington. It grows by streams, in canyons, and near woodland lakes. These sites often have moist soil and some shade.

This shrub grows fast into an upright, round bush. It has many stems. Shoots from its roots can form a thicket. Garden plants reach about 6–12 feet (1.8–3.7 metres) tall and wide. RHS gives an upper size of 13 feet (4 metres). Some plants reach 15 feet (4.6 metres) tall. Plants may grow taller in shade than in sun. The gray-brown bark has small pores. It grows scaly with age. Brown twigs have fuzzy buds and give off a smell when broken. Oval leaves grow in pairs, with smooth edges. Their dark green tops feel rough. Fine hairs cover the leaves beneath. The leaves turn yellow in fall.

Single flowers grow at branch tips from late spring through summer. Missouri Botanical Garden gives June through August as the bloom period. Bloom may last into early fall in some years. The flowers span about one to three inches across. Their narrow petals and sepals make them look like waterlilies. Colors range from dark red to purple-brown. Some people find the scent sweet; others find it unpleasant. Each flower lasts only one or two days. The bowl-shaped fruits hold many small achenes. The fruits turn from green to brown and become woody. They ripen in late summer and can stay through winter.

Grow this shrub in sun or partial shade. It also copes with deeper shade and many soil types. It grows best in rich, moist loam that drains well. It accepts acid soils, neutral soils, and alkaline soils. It needs a moderate amount of water. Missouri Botanical Garden lists USDA zones 6–9. RHS rates it H6. Cold sites near its hardiness limit need shelter. They also need mulch over the roots. Prune once blooms end and remove root shoots you do not want. Use it in hedges, shrub borders, or woodland gardens.

Serious pest and disease problems are rare. Honey fungus can occur, though. RHS warns that eating it can harm people and pets. PFAF records dried bark as a spice but urges caution. It also notes past bark uses for throat, cold, and stomach complaints. Flowers yield a brown dye. People used fresh shoots to make baskets.