Echinocereus dasyacanthus aka Texas Rainbow Cactus

Echinocereus dasyacanthus is a small cactus called Texas rainbow hedgehog or yellow pitaya. It belongs to the cactus family, Cactaceae. Its native range covers the southern United States and northern Mexico. It grows in desert scrub and grassland, including sandy valleys. It also lives on rocky slopes and limestone canyon sides. These wild sites lie in dry country with sparse plant cover.

Plants grow upright, with one stem or several from the base. Older plants may form loose clumps with fewer than 20 stems. RHS gives a garden height of 0.3–1.6 feet [0.1–0.5 metres]. Its listed spread reaches about 0.3 feet [0.1 metres]. LLIFLE describes shorter stems, mostly 0.3–0.7 feet [0.1–0.2 metres], sometimes 1.3 feet [0.4 metres]. The stems start egg-shaped, then become more like columns. Each has about 15–20 ribs beneath a dense coat of spines. Spine colours include pink, pale yellow, white and tan. Some plants show bands of different colours from each year's growth. Older spines turn grey.

Large, scented flowers open in spring, from March through May. LLIFLE gives April to May as its flowering season. The blooms are mostly yellow, with green near the base. Some take on salmon or magenta tones as they age. Flowers reach about 0.3 feet [0.1 metres] across. The spiny fruit turns dull purple or maroon, though some stays green. Its flesh ranges from white to pinkish purple. The fruit is edible but has a sour taste. Crops can be uneven, and ants may spoil the harvest.

Give this cactus full sun and soil that drains well. RHS accepts loam or sand across acid, neutral and alkaline conditions. For pots, it recommends peat-free, loam-based compost with extra grit. Water moderately during growth, then stop watering while the plant rests. Feed with balanced liquid fertiliser two or three times during growth. Hardiness guidance differs: RHS assigns H1C and recommends growing under glass. PFAF lists USDA zones 6–9. These ratings do not give one clear outdoor cold limit.

Its spines and large blooms suit pots and patio displays. RHS gives five to ten years to reach full size. Grow new plants from seed; the plant needs no pruning. Mealybugs and scale insects may attack it, but disease is uncommon. PFAF reports no toxicity to people or pets. Spines still pose a handling risk and can lodge in skin. Use gloves or tools when handling plants and fruit.