Perennials are hardy plants: they survive every winter, again and again. When they emerge in the spring, they’ll be bigger and healthier than ever. This means you can enjoy these tough guys year after year!
To survive periods of freezing temperatures, hardy plants have a way of tolerating extreme cold. It’s called cold hardening. In this process, the quantity of water in the plant decreases while the sugar level in the plant cells increases. It’s as if the plant produces antifreeze to keep itself from freezing. Some plants are better at this than others, and perennials are at the top of the list.
The foliage of most perennials, such as Delphinium, Japanese Anemone and Caucasian Forget-me-not, dies in autumn. The rest of the plant stays hidden away underground during the winter. If you look closely, however, you can often see the shoots of next year’s growth that will emerge again in the spring.
Evergreen hardy plants
Other perennials are evergreen plants. They retain their leaves year-round. Good examples of evergreen perennials are the Christmas Rose (Helleborus), Coral Bells (Heuchera) and the Elephant-eared Saxifrage (Bergenia). These plants add colour and visual attractiveness to your garden or balcony all year long.
When autumn arrives, you can simply let the foliage of hardy plants wither and die. If you don’t remove them, these stems and leaves will provide an insulating layer to give the plants extra protection against the cold. Insects and small mammals can also use this ‘winter blanket’ as a shelter. And some plants, such as Silvergrass (Miscanthus), retain a beautiful silhouette you can enjoy during the autumn and winter seasons.
Since plants in pots are more susceptible to frost damage, move them to a sheltered location or wrap the pots temporarily in jute, horticultural fleece or other insulating material during periods of freezing temperatures.