Friday, February 18, 2011

Opuntia (Prickly Pear Cactus)

Prickly pear is the common name for plants that belong to the genus Opuntia, which is one of the largest groups of cacti with over 360 species. They grow in abundance in much of Mexico, and in the west, southwest and eastern United States. In addition, because they are so cold-tolerant, they can be found growing all the way up to northern Canada. Plants vary in size from 5 centimeter (2 inch) miniatures to 30 meter (100 foot) tree-like specimens.

Opuntia is generally separated into two groups, Cylindropuntia and Platyopuntia, the latter being the one referred to as prickly pear cactus for its production of spiny, (usually) edible fruit. The Platyopuntia have round, flattened joints called pads that are covered with sharp, barbed spines that can easily tear the skin and cause severe irritation. Flowers shaped like cups or saucers, usually yellow in colour but also available in shades of red, purple and even orange, are produced from spring to fall.

A prickly pear cactus will flower when it is a few years old, but don’t be disappointed if yours doesn’t. Opuntias are not the easiest cacti to bring into bloom indoors. One can certainly try though, by providing the ideal conditions, which include summer care, winter neglect (cooler temperatures and less water) to a prickly pear that is slightly pot bound.

Like most cacti, the popular prickly pear requires high levels of light to grow properly. Choose the sunniest spot available, especially during the winter months. Depending on where you live, and whether there are any other obstacles (trees, buildings, bushes) between the light and your plant, the sun may need to be filtered with sheer curtains in the hottest months. If the plant is placed where there is insufficient light, growth may be malformed and stems will be elongated.

When the plant is actively growing in spring and summer, water thoroughly after the medium begins to dry out. Succulent-type plants are highly-susceptible to rot, and the prickly pear is no different, so make sure you use an airy soil that drains quickly. Grow the plant in a container that is just large enough to support the root system and repot only when essential. Reduce watering in late summer; allow the soil to dry out. During the winter, keep the plant dry; water just enough to prevent shriveling. Be very careful during the colder months. Most prickly pears are killed by over-watering during the winter.

From spring to autumn, prickly pears will do well in average room temperatures that are typical to most homes. In the winter they should be given a rest period in a cooler area where temperatures range between 10°C - 13°C (50°F – 55°F). Low humidity is not an issue. Although the plants don’t mind dry air, they do mind if it’s stagnant. Keep the air fresh and in constant motion by running floor or ceiling fans, and by opening up windows regularly; air that is circulated and kept fresh helps discourage pest infestations.

This cactus is particularly easy to grow, requiring nothing more than a sunny location, careful watering and a cool winter rest. If you can provide these basic needs, don’t hesitate to pick up a prickly pear cactus.

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