Austrocylindropuntia subulata aka Eve's Pin

Austrocylindropuntia subulata is a cactus known as Eve's needle. It forms an evergreen shrub or a small tree. Kew places its native range from Peru to Bolivia. Other sources include Colombia or suggest an origin in Peru alone. It grows in dry Andean valleys and scrub. It also occurs beside rivers and on disturbed ground. People grow it far beyond its native range.

This fast-growing cactus has upright stems and many long branches. Sources give heights of about 10–13 feet [3–4 metres]. Some plants reach 16 feet [5 metres], but garden plants stay smaller. The listed spread reaches 5 feet [1.52 metres]. Older plants form a woody trunk with dark brown bark. Young stems are green, round, and marked with raised tubercles. Each tubercle bears an areole where sharp spines grow. The pale spines reach about 0.26 feet [0.08 metres] long. Fleshy, awl-shaped leaves are green to yellow-green. They can remain on the plant for over a year.

Flowers appear in spring or summer, near the branch tips. Their tubes reach about 0.25 feet [0.08 metres] long. Colors include red, orange-red, yellow, and greenish-yellow. Plants in pots seldom flower. The egg-shaped fruit changes from dark green to red. Fine, barbed hairs called glochids cover the fruit. NC State reports that the fruit is edible. People can also ferment it to make wine. Useful Tropical Plants lists no known food uses.

Give this cactus full sun, or strong light indoors. It needs soil that drains well and dries between waterings. A cactus mix with coarse sand, pumice, or perlite suits it. Pots need holes that let excess water drain away. It needs little water and suits dry gardens. Sources list USDA zones 9–10 or 9–11. Reports of frost tolerance differ, so protection from freezing is prudent. It serves as a specimen in rock and succulent gardens. People also use it for living fences and erosion control. Its branches provide shelter for birds and small animals.

Mealybugs and scale can attack, though most pests cause few problems. Wet soil can cause root rot; high humidity can rot stems. Strong sun can scorch the plant. NC State lists it as non-toxic to cats, dogs, and horses. Its spines and glochids can still injure skin. Keep it away from paths and children's play areas. It has escaped gardens and become invasive in several regions. Dense stands crowd out other plants and harm people and animals.