Say it: py-loh-soh-SEER-ee-us. Common names: tree cactus, blue torch, old man of the tropics.
Where it grows
Warm regions from Mexico and the Caribbean to Brazil. Pilosocereus azureus (often sold as P. pachycladus) and P. glaucescens come from eastern Brazil; P. bradei (sometimes placed in Cipocereus) from Minas Gerais, Brazil; P. palmeri from northeastern Mexico.
Size and growth
Columnar, branching cacti that become small trees of 10–30 feet. Grown for color: azureus, glaucescens and bradei have powder-blue to turquoise stems that look painted, while palmeri develops thick white wool near the top in full sun. Fast growers — a seedling can be a foot or two tall in a few years with warmth and water.
Flowers
Night-blooming, bell-shaped flowers along the upper stems in summer, pollinated by bats and moths. Palmeri's flowers smell strongly of squash or pumpkin. Plants need several years and some height before flowering.
Care
- Light: full sun for the best blue color and wool.
- Water: generous in summer, sparing in winter.
- Soil: fast-draining.
- Cold: frost-tender. Keep above about 35°F; bring potted plants in for winter in cold areas. Palmeri takes our 115°F summers with little water.
From seed
Easy, germinating in 7–21 days. Seedlings are green at first and turn blue as they size up in strong light.
P. azureus seeds · P. glaucescens seeds · P. bradei seeds · P. palmeri seeds