Opuntia humifusa aka Creeping Prickly Pear

Opuntia humifusa, or eastern prickly pear, belongs to the cactus family. This evergreen succulent grows in the eastern United States and Mexico. Kew lists Mexican populations in Tamaulipas and San Luis Potosí. Some garden sources extend its range north into southern Ontario. It grows in open, dry places with sand or rock. These include grasslands, dunes, rocky slopes, and stream valleys.

The plant forms low clumps and spreads along the ground. Garden plants reach about 0.5–1.2 feet [0.15–0.36 metres] tall. They spread about 1–1.5 feet [0.30–0.46 metres] wide. Chicago Botanic Garden reports an unusual height of 4 feet [1.22 metres]. Wild colonies can exceed 3.3 feet [1 metre] across. Loose pads can take root beside the parent plant. Growth is slow, and the roots stay shallow. The round or oval green pads are swollen stems, not leaves. They store water and carry out the work of leaves. Small, short-lived leaves also occur. Pads may turn purple and shrink during winter. They swell and regain their green colour in spring.

Tiny barbed bristles, called glochids, grow in clusters on the pads. Sources disagree on whether this species also bears long spines. Large yellow flowers open near the ends of the pads. Some have red centres, and bees visit them. June to July is the best-supported bloom period. Other sources report blooms earlier or later in the season. Insects pollinate the flowers. Fleshy fruits turn from green to red or purple. They ripen from late summer into autumn and may last through winter. Birds and box turtles eat them.

Give this cactus full sun and soil that drains well. Sandy or gravelly ground suits it best. Clay can work where water does not linger. It tolerates drought, salt, and dry, rocky soil. Missouri Botanical Garden lists USDA zones 4–9. Use it in rock gardens, pots, borders, or dry slopes. It can also cover a small patch of ground. Pad cuttings offer an easy way to make more plants. Seed growing takes more effort.

Serious pest and disease problems are uncommon. Scale insects and mealybugs may occur. Wet soil can cause root rot. The fruit and pads are edible, raw or cooked. Fruit also serves for jam and sweets. Remove all bristles before preparing either part. Their barbs lodge in skin and cause painful irritation. NC State lists it as non-toxic to cats, dogs, and horses.