With freezing temperatures coming, here's how you can protect your plants

Daffodils are deceptive flowers.

The same goes for magnolias, those beguiling blooms that trick the restless gardener into thinking it's time to load up on supplies at greenhouses and nurseries.

Mother Nature, in the sneakiest of seasons, always gets the last laugh.

A harsh cold front will likely send temperatures below freezing Tuesday and Wednesday nights across the Chicago area. Normal highs this time of year should be in the low 60s, with normal lows around 40.

The late-season cold snap has left the plant clinic at the Morton Arboretum in Lisle buzzing with hotline calls and emails from anxious gardeners. Plant guru Julie Janoski helps ease their minds with some helpful advice and perspective.

“For most plants, there's nothing to be overly concerned about,” said Janoski, the plant clinic manager. “Most plants can take a freeze.”

But if you've already planted annuals or even some vegetables, you'll need to cover those for the next couple of nights with plastic or sheets.

During the day, when temperatures are supposed to reach above freezing, don't leave plants covered. Trapping moisture on their leaves could cause fungal diseases. At night, make sure the coverings are touching the ground to hold heat underneath.

Snow also would act as an insulating blanket for sensitive plants. Tuesday's forecast calls for a mix of rain and snow, with possibly slushy conditions, especially east of I-55. But northern areas may not see much accumulating snowfall, National Weather Service meteorologist Kevin Birk said Monday.

“The snow is nothing to be concerned about. The issue is really the cold,” Janoski said. “Once it gets down to 27, 28 degrees, we consider that a hard freeze, and that can do some damage to plants.”

The colors of spring could look a bit duller for a week or two. But you can still look forward to many spring showstoppers at the arboretum. Crabapples, most of the spring perennials, tulip trees and some viburnums have yet to bloom and should be fine, Janoski said.

After seasonably warm weather returns later this week, try to cultivate some patience. Typically, gardeners should wait until sometime in early May to get back to tending their little piece of earth.

“Don't plant your annuals until Mother's Day,” Janoski said, “and this is why.”