April frost could damage March gardens in suburbs

Suburban streets are lined with flowering trees. Garden centers are raking in the green. Runners are out and about, and record-breaking highs have become the norm.

While these past two weeks of unprecedented warmth have been a pleasant sequel to arguably the mildest winter in years, meteorologists and some gardeners and business owners fear for the worst — a frost.

The spring flower season, local fruit production and gardeners' gamble to produce the earliest tomato ever all could come to an end with a hard frost.

“Based on what's happening, I would put the chances of that occurring at pretty high,” said Richard Castro, a meteorologist with the National Weather Service. “There's still cold air around mid-America in April.”

There is a 90 percent chance of another freeze by April 5, according to historic averages.

The date of the last spring freeze of the season ranges from March 16 to May 25.

“We are having growing conditions that we typically see in May,” said Bruce Branham, a professor in the Department of Crop Science at the University of Illinois.

Those May-like conditions have flowering plants and fruit trees more than a month ahead of schedule and many plants are in full bloom, said Ed Hedworm, manager of plant records at the Morton Arboretum in Lisle.

Hedworm said part of his duties involve recording bloom dates and keeping detailed records for the 1,700-acre arboretum.

“I haven't seen anything like this, and I've been working at the arboretum for 35 years,” he said. “This is very unusual.”

After a record nine consecutive days of breaking or tying record highs, which ended Thursday, the current average temperature for March of 53.5 degrees would make this the seventh warmest April ever.

That consistent heat, and lack of a cool period in between, is what has experts worrying and plants going into full bloom.

“Generally in April you might have a day in the 80s and one in the 60s, but the longer this stays, the further along everything is going to get,” Branham said.

“The greatest danger is if we have a freeze after these plants are actually out and in bloom,” Hedworm said. Some plants simply won't survive.

The warm weather's early bloom season has boosted garden centers' business much earlier than usual, but owners are quick to warn customers against purchasing certain plants that could be susceptible to frost.

“I just tell them, unfortunately the temperature says it's beautiful out, but the calendar says you're six weeks too early,” said Chris Pesche, owner of Pesche's Flowers in Des Plaines. “We are selling tomato plants, but we warn people. People are just trying to have some fun.”

Business at Pesche's is up more than 40 percent compared to this time last year, according to the owner, but he fears the weather could lead to an early and short season for flowers and a fruitless summer for plants if a frost hits.

“Last spring the forsythias lasted almost five weeks,” he said. “This year they are going to last seven to 10 days and they are full blooming already.”

All it would take is a cold breeze off the Lake Michigan to destroy the flowers on many of the plants that are in full bloom already, according to Pesche.

His advice for those looking to take advantage of the weather is to plant flowers that can handle a frost, and keep anything else that could be damaged in a pot so that it can be moved inside.

“Everyone always wants to be the first tomato on the block,” he joked. “You have to play it safe.”

For gardeners taking a risk and putting early bloomers into the ground, if the forecast does call for a drop in temperatures, a loose covering of mulch or newspaper will protect most plants, Hedworm said.

Presuming a frost does occur, one place consumers could see the impact will be at farmers markets and farm stands, according to Branham.

“Not a lot of the produce we eat is grown without our region,” Branham said. “But it could have a big impact on the burgeoning local foods effort where we see more and more people trying to grow stuff locally to get fresher and better tasting food.”

The warm spring has been felt throughout much of the Midwest and in Michigan — areas that supply most of our fruit, especially apples and peaches, he said.

Meteorologists across the state are fearful of a repeat of the “killing freeze” that swept through in April 2007 after one of the warmest Marches on record, according to Castro.

“It was a tremendously damaging freeze for the Midwest,” he said.

That March, the average temperature was more than 7 degrees higher than usual. The freeze rolled through in early April and caused more than $146 million in damage to the agricultural industry, according to an Illinois State Water Survey report.

“Mother Nature will do her things, and there's not much we can do to prepare for it,” Hedworm said.