Ice burn threatens perennials and lawns in spring and winter

Ice burn is a phenomenon of mild winters with little snow, which can kill even the hardiest perennials in the garden. An expert explains how to prevent damage.

When spring comes, the gardener may be surprised when the perennials no longer sprout from the ground and there are bare patches in the lawn. The cause may be the so-called ice burn, which has destroyed perennials, lawns and onion flowers in recent years.

The background of the phenomenon is winters with little snow. When the ground is wet and the weather freezes, the moisture freezes on the surface of the ground into a dense crust of ice, which suffocates the plants.

“Plants don’t get oxygen under the bark, and plant diseases can spread”, CEO of the Gardening Association Timo Taulavuori says.

The risk of an ice burn does not necessarily ease, even if a new layer of snow falls on top of the ice sheet. The ice crust only gets stronger if the snow that has fallen melts and freezes on top of the already existing crust.

The risk of ice burn is greatest in March–April, when the temperature hovers on both sides of zero.

Ice burns are an increasingly common phenomenon

With climate change, ice burns will probably become more common. In the spring of 2023, ice burn may become a problem.

“This year it has been such a mild winter that there is some fear that the plants will be destroyed. A possible cold spring will only make the situation worse,” says Taulavuori.

Read also: Can onion flowers get frostbite if they peek out of the flower bed too early? An expert gives advice on the protection of spring flowers – if done incorrectly, the splendor of the flowers can be destroyed

How can you avoid ice burn?

Some plants can withstand frostbite better than others. For example, woody plants and bulbous flowers are more persistent survivors than herbaceous plants.

Thick ice melts very slowly even in sunlight. The gardener should be a little careful about the melting of the ice in order to prevent damage.

“You can break up the ice cover that has formed on the perennial bed, for example with an iron rod. Another way is to pour lukewarm water on the ice during the day. If the sun is shining, you can spread sand or ash on top of the ice crust, which heats up quickly, and thus melt the ice,” Taulavuori advises.

If the plant shoots a green shoot in the spring, you know that it has survived the frostbite.

“Some of the grass-stemmed plants are clearly slower to wake up from the winter in spring, so for example you should wait patiently for the sprouting of moonshine. Healthy roots and even a small green beginning under the surface soil indicate that the plant has survived the winter into the new growing season.”