Stenocereus thurberi aka Organ Pipe Cactus

Stenocereus thurberi is the organ pipe cactus, also called pitahaya dulce. It belongs to the cactus family, Cactaceae. Its native range runs from southern Arizona into northern Mexico. It grows in Sonoran desert scrub and dry forest. Plants live on plains, slopes, and rocky ledges. Near the northern limit, warm slopes help shield them from frost.

This large cactus forms a shrub or a tree-like clump. Garden references give a height near 20 feet [6 metres]. Clumps can spread to 15 feet [4.6 metres] wide. Wild plants vary in size and shape across their range. Northern plants send up many stems from near ground level. Southern plants may branch higher and form one or more trunks. Larger plants reach 26–39 feet [8–12 metres], sometimes more. The upright stems give the clump its organ-pipe shape.

The stems have thick, green skin with 12–17 raised ribs. Individual stems can be about 0.5–0.7 feet [0.15–0.20 metres] thick. Dark spines grow in rows along these ribs. Each areole holds a cluster of spines. The longest central spines reach about 0.16 feet [0.05 metres]. Older spines turn grey. Flowers grow near the stem tips and open at night. Virginia Tech describes white to purple blooms with white edges. Chicago Botanic Garden lists red flowers. Bloom records span March through August, including early summer. Each flower lasts less than a day. Bats pollinate the flowers.

The round fruits turn from green to red as they ripen. Young fruits have many spines, which fall away with ripening. People eat the sweet pulp and seeds fresh. They also make jam from the fruit. The thick, soft rind comes away from the pulp. Fruit can cause red urine after eating. Useful Tropical Plants reports no known hazards. This does not establish safety for pets or every plant part.

In cultivation, this cactus needs full sun and dry soil. Chicago Botanic Garden places it in USDA zones 9–11. LLIFLE reports survival at −4°C, but frost can harm stem tips. People grow it as a living fence beside roads and gardens. Dried stems provide fuel and torch material. Woody ribs supply material for fences, homes, and tools. Traditional medicine uses heated, spineless stem pieces for aches. The species has a reported Least Concern conservation status. Farm clearing and fires have damaged some wild stands.