Common Name: Twist-Spine Prickly Pear

General Information

Opuntia macrorhiza is a spiny, succulent, evergreen shrubby cactus forming a low clump of growth around 13cm tall and 2 metres or more wide[].
The plant is harvested from the wild for local use as a food, medicine and source of materials.
Opuntia macrorhiza has a very wide range, is abundant, and there are no threats. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2017)[].

Known Hazards

The plant has numerous minutely barbed glochids - these are barbed spines that are usually small to minute and are very sharp and brittle. The glochids are very easily dislodged when the plant is touched and can penetrate the skin where, because of their barbs, they become stuck and are very difficult to see and remove. They can cause considerable irritation and discomfort[, ].
Opuntia species can contain quite high levels of oxalic acid, especially in older parts of the plant. Perfectly alright in small quantities, foods containing oxalic acid should not be eaten in large amounts since it can lock-up other nutrients in the food, especially calcium, thus causing mineral deficiencies. The oxalic acid content will be reduced if the plant is cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition[, ].

Botanical References

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Range

Central and southern N. America - Utah to Missouri, south to northern Mexico, Arizona, New Mexico and Texas

Habitat

Sandy, gravelly or rocky soil in grasslands, xerophyllous scrub and pine-juniper forests; at elevations from 600 - 2,100 metres[, ]. Plants can sometimes persist for years under invading trees[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	0.12 m
Pollinators	Bees, Insects
Cultivation Status	Wild

Cultivation Details

Opuntia macrorhiza is a fairly cold tolerant plant, requiring an arid or semi-arid climate with hot summers.
Requires a sandy or very well-drained soil[]. Prefers a pH in the range 6 to 7.5[]. Plants must be kept fairly dry in the winter but they like a reasonable supply of water in the growing season[]. A position at the base of a south-facing wall or somewhere that can be protected from winter rain is best for this plant. Requires warmth and plenty of sun. Plants tolerate considerable neglect.
This species is closely related to Opuntia humifusa[].

Edible Uses

Fruit - raw, cooked or dried for later use[, ]. Sweet and gelatinous[]. Lean and insipid[]. The unripe fruits can be added to soups etc, imparting an okra-like mucilaginous quality[]. The fruit can hang on the plant all year round[]. Be careful of the plants irritant hairs, see notes above. The fruits are about 4cm in diameter and usually free of spines[].

Stem segments - cooked or raw[]. Watery and very mucilaginous[].
The tender young stem segments of various species are often cooked as a vegetable[]. Known as ‘nopals’ in Mexico, where they are a common ingredient in numerous dishes, they can be eaten raw or cooked, used in marmalades, soups, stews and salads. The most commonly used species are Opuntia ficus-indica or Opuntia hyptiacantha (syn Opuntia matudae), although the stems of almost all Opuntia species are edible[, ].

Seed - dried or briefly roasted then ground into a powder[].

Medicinal

The spines are used to lance skin infections[].

The stem segments are roasted to obtain a lubricant that is used in childbirth[].

We have no further specific information on medicinal uses for this species, but the following notes are likely to apply universally to Opuntia species and other related genera[].

The flesh of tender young stem segments can be applied as a poultice to reduce inflammation[].
The mucilage and soluble fibre found in the flowers and stem segments have been shown to help control blood-sugar levels associated with adult-onset diabetes[].
There is clinical evidence that the soluble fibre in the stem segments helps reduce blood cholesterol levels[].

Other Uses

The following notes are for Opuntia ficus indica. They almost certainly also apply to this species[].

A gum is obtained from the stem. It is used as a masticatory or mixed with oil to make candles[]. The juice of the boiled stem segments is very sticky. It is added to plaster, whitewash etc to make it adhere better to walls[].

Propagation

Seed - sow early spring in a very well-drained compost in a greenhouse. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first two winters. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Give the plants some protection from winter wet. Make sure you have some reserve plants in case those outdoors do not overwinter.
Cuttings of leaf pads at any time in the growing season. Remove a pad from the plant and then leave it in a dry sunny place for a couple of days to ensure that the base is thoroughly dry and has begun to callous. Pot up into a sandy compost. Very easy, rooting quickly.