How to Overwinter Cacti Outside in Colder Climates

Growing cacti outdoors in a colder climate feels like a contradiction, but it is more doable than most people expect. A surprising number of cactus species can handle freezing temperatures, and even the more tender varieties can be protected through winter with the right approach.

Frost-Tolerant Cactus Varieties

Several cacti have evolved in high-altitude or northern regions where winter temperatures regularly drop below freezing. These species have developed the ability to survive frost and even prolonged cold.

Opuntia (Prickly Pear)

Many Opuntia species are remarkably cold-hardy. Opuntia humifusa, the Eastern prickly pear, is native to much of the eastern United States and can handle temperatures well below zero degrees Fahrenheit. It is commonly grown in zones 4 and 5. The pads may shrivel and look dead in deep winter, but they recover with warmer weather.

Escobaria and Pediocactus

These smaller, globe-shaped cacti are native to mountainous regions of the western US and can tolerate extreme cold. Escobaria vivipara is hardy in zone 4. They stay small and are a good choice for a rock garden in cold climates.

Echinocereus (Hedgehog Cactus)

Several hedgehog cactus species tolerate moderate freezing. Echinocereus triglochidiatus, or claret cup, handles temperatures down to about 0 degrees Fahrenheit in dry conditions and produces brilliant red flowers in spring.

The Key Factor: Dry Cold vs. Wet Cold

Cold-hardy cacti can handle freezing temperatures in their native arid environments because the cold comes with very dry conditions. Wet cold is a different story. When a cactus absorbs moisture and then freezes, the water inside expands and damages cell walls. This is why cacti that survive -10 degrees Fahrenheit in a dry mountain climate often fail at 25 degrees Fahrenheit in a wet Pacific Northwest winter.

If you live somewhere with wet winters, the primary protection strategy is keeping water off the plants, not just keeping them warm.

Protecting Less Hardy Cacti Through Winter

Bring them inside

The simplest solution for container-grown cacti is to move them indoors before the first frost. A cool, bright room or unheated garage with a window works well. Keep them dry during winter dormancy.

Cover them

For in-ground or large container cacti that cannot easily be moved, a simple frost cloth or burlap cover draped over the plant during hard freezes provides meaningful protection. Remove it during warmer days to allow light and air circulation.

Improve drainage

In rainy climates, planting cacti on a slope or in a raised bed with very gritty soil reduces the moisture they are exposed to in winter. A layer of gravel around the base of the plant helps keep the crown dry.