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This is the largest and most widespread genus of cacti, numbering
more than 200 species and occuring in the wild from southern Canada
almost to the southern tip of South America, as well as the West
Indies and Galapagos Islands.
They range from tiny prostrate plants with tuberous roots to trees
over 30 ft (9 m) tall. The branches are constricted at regular
intervals to form joints that may be broad and flattened or
cylindrical and sometimes covered in tubercles.
All have small, fleshy leaves at the growing tips that usually fall
off soon after they appear.
Most of the species have sharp spines (sometimes barbed) as well as
small bristles that are extremely hard to remove from the skin, so
care should be taken to position these plants away from areas where
children or animals play.
The flowers are generally yellow or red, sometimes quite showy, and
are followed by edible fruits (prickly pears), which range in shade
from green to yellow to red.
Several species have become serious pests in some warmer countries,
the worst being Opuntia stricta in Australia and South Africa early
in the twentieth century; their spread was eventually checked by
biological control, using the cochineal insect and the cactoblastus
moth.
Flowering colors: Green, Orange, Pink, Purple, Red, Yellow
Cultivation: These plants thrive in hot, dry conditions in
moderately fertile, gritty, humus-rich, well-drained soil and full
sun. Propagate from seed or detached joints . |
