Introduction
This native is in danger of extinction in Florida (Fig. 1). It forms irregular clumps or shrub-like mounds in sandy soils, and has a very coarse texture. The leaves of prickly pear cactus are inconspicuous, however the plate-like sections of the stem are often thought of as leaves. These plate-like sections are actually modified stems and reach a length of 2 to 6 inches. Stem sections remain green with age and are covered with 3-inch-long spines. Very minute spines (glochids) are located in the numerous areoles. The larger spines are quite painful, however the minute spines cause a lot of irritation if they are captured in clothing or attach to the skin surface.
General Information
Scientific name: Opuntia spinosisima
Pronunciation: oh-PUN-shee-uh spy-noe-SIS-sim-muh
Common name(s): prickly pear cactus
Family: Cactaceae
Plant type: shrub
USDA hardiness zones: 3B through 11 (Fig. 2)
Planting month for zone 7: year round
Planting month for zone 8: year round
Planting month for zone 9: year round
Planting month for zone 10 and 11: year round
Origin: native to Florida
Uses: mass planting; border
Availability: grown in small quantities by a small number of nurseries
Description
Height: 3 to 20 feet
Spread: 3 to 15 feet
Plant habit: spreading; upright
Plant density: open
Growth rate: moderate
Texture: coarse
Foliage
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: entire
Leaf shape: elliptic (oval)
Leaf venation: none, or difficult to see
Leaf type and persistence: deciduous
Leaf blade length: less than 2 inches
Leaf color: green
Fall color: no fall color change
Fall characteristic: not showy
Flower
Flower color: orange; red; purple; white
Flower characteristic: summer flowering
Fruit
Fruit shape: oval
Fruit length: 1 to 3 inches
Fruit cover: fleshy
Fruit color: red
Fruit characteristic: suited for human consumption; persists on the plant
Trunk and Branches
Trunk/bark/branches: showy; thorns present
Current year stem/twig color: green
Current year stem/twig thickness: very thick
Culture
Light requirement: plant grows in full sun
Soil tolerances: sand; acidic; slightly alkaline; loam
Drought tolerance: high
Soil salt tolerances: good
Plant spacing: 24 to 36 inches
Other
Roots: usually not a problem
Winter interest: no special winter interest
Outstanding plant: plant has outstanding ornamental features and could be planted more
Invasive potential: not known to be invasive
Pest resistance: no serious pests are normally seen on the plant
Use and Management
When the flowers of this plant are produced in large numbers, as on vigorously growing individuals, they put on quite a show. The plant will bloom over a period of several weeks, however the individual flowers only last one day. The flowers are cup-shaped, bright red, appear on the outermost plate-like stem sections, and are 2 to 3 inches wide. The showy berries may reach a length of 2 to 3 inches and are red to purple at maturity (mid to late summer). These fruits may be eaten after the spines and glochids have been singed off with fire, and the seeds of the fruits can be roasted for flour.
These plants are well-suited to hot, dry conditions. Prickly pear cactus can be used as a specimen in areas of a dry, rocky, unirrigated landscape. An established row of these makes an impenetrable border for pedestrians.
This plant is drought, salt, and heat tolerant. It requires a sunny, well-drained site and is tolerant of sandy, alkaline soils. Prickly pear will only tolerate wet conditions for a very short period of time.
Propagation is by division because the seeds of many species are difficult to germinate. The plate-like sections can be placed on slightly moist sand to obtain rooting.
Pests and Diseases
Opuntia spp. have no pests nor diseases of great concern. Root rot can be a problem in wet locations.
