Hardy cacti? Believe it or not, yes! It’s true that most of these prickly succulents are not winter hardy, but a few oddballs have adapted to thrive in even the coldest parts of the country. Some of the best are Opuntia species, commonly known as pricklypears. These plants offer lovely spring flowers and striking, paddle-shaped stems that lend interest in a number of sunny garden situations, from rock gardens to exotic container plantings.
Opuntia is a diverse and widespread genus of 150-200 species existing from Canada down to Argentina. They’re most easily characterized by their paddle-shaped, photosynthetic stems (joined and extended in segments), large, showy flowers and bulbous red fruit that clusters along the paddles late in the season. As many people might expect from a cactus, Opuntia spines are pointy, but they’re more unique than those of your average cacti. The needles are sharp and long, and the areoles (sites where the spines arise) have clusters of glochids – minute, brittle, barbed spines that detach easily and become embedded in the skin. (Ouch!)
Of all the Opuntia species, only several are adapted to colder climates. They exist in more northerly states or at higher altitudes and have physiological adaptations that enable them to fight the cold. When temperatures begin to drop toward freezing, the plants’ pads lose water and appear to deflate. This water loss protects the plants from freezing damage. The pads also turn from bright green in summer to shades of reddish-brown and burgundy in winter – a color change that lends protection from winter sun damage.
Hardy pricklypears aren’t always the easiest to find, but a few are commonly available and highly garden-worthy. The more popular and available plants are usually the best for budding cactus enthusiasts to try. Here are four hardy species worth considering:
Opuntia fragilis (brittle pricklypear). Featuring creamy-yellow summer flowers, Opuntia fragilis is the hardiest of all the pricklypears. This remarkably cold-tolerant species is native to grasslands, limestone outcrops, gravely sites and alpine and subalpine regions as far north as northern British Columbia in Canada. It’s distinguished by smaller, slightly rounded pads and is commonly found growing on rocky outcrops, so it’s perfect for rock gardening. Unlike nearly every other Opuntia species, brittle pricklypear can take light shade, and even though it grows in the coldest of regions, it can also take some heat.
The beautiful and prolific Opuntia humifusa (devil’s tongue) is the most common of the hardy pricklypears. It can be found in drier, rocky or sandy sites east of the Rockies. Those living along the Atlantic Coast may be familiar with devil’s tongue because it’s native to coastal plant communities and often planted due to its remarkable tolerance to salt, wind and high heat.
In late spring or early summer, devil’s tongue produces lots of large, bright yellow or orangish-yellow flowers along its pads. These glow in the sun and are favored by bees, which become covered in the dusty, yellow pollen of their anthers. By fall, deep red fruit appears along the pads and persists into winter. As this pricklypear ages, its pads drop to the ground and root, so over time a single plant can form a substantial clump.
The name Opuntia phaeacantha (tulip pricklypear) sounds ornamentally promising, doesn’t it? The tulip-shaped flowers of this hardy, western pricklypear bloom in late spring or early summer. Floral color varies widely and may be yellow, apricot, pink or red. (Those in the pink and red range are the most striking and interesting.) All offer red fruit in fall. The broad pads are armed with fierce spines that are as painful as they are visually interesting. There are several notable cultivars to choose from, including the apricot-flowered ‘Plum’ and the orangish-coral-flowered ‘Persimmon’ – both hybrids created by Claude A. Barr, a Great Plains cattleman and noted native plant hybridizer.
Dense areoles and spines cover the pads of the prickly wonder, Opuntia polyacantha (plains pricklypear). Large, chalice-shaped flowers of clear yellow or orangish-red appear in late spring or early summer, and brownish-red fruit follows later in the season. Hardiness level depends on where the plant comes from. Its native distribution extends from western Texas all the way up to Alberta, Canada.
With minimal care and effort, you can have a handsome Opuntia planting. The best way to start growing these great plants is in a trough or large container. Full sun and coarse, sharply drained soil with a neutral pH is needed for best growth and flowering. Top-dress the soil’s surface with natural-looking pebbles for a clean, attractive look. As with all sharp and potentially dangerous plants, pricklypears should always be handled with thick, rose gloves and planted away from areas where small children and pets play – yet still kept in a spot where they can be enjoyed for their unique, striking beauty.