KC’s early spring could lead to damaged plants if late frost, freeze strikes

The crocuses and daffodils are blooming. Plants are coming out of dormancy. And buds are starting to appear on tree limbs.

It’s enough to make you think it’s spring in Kansas City.

While the string of recent warm days might have you nodding your head in agreement, a glance at the calendar says otherwise.

“Definitely, everything is a little ahead of schedule,” said Dennis Patton, a horticulture agent for the Johnson County Kansas State University Research and Extension Office in Olathe.

With the mild winter, some lawns never lost their green cast, and weeds are loving this weather, too.

With spring getting an early jump, there is reason to be concerned, especially if temperatures remain on the warmer side.

“As long as our plants are pretty well in a tight bud formation, they have pretty good resilience to cold weather,” Patton said. “The more the buds open up and expand, their ability to tolerate cold weather decreases.”

The worst-case scenario would be that it continues to be warmer than usual, everything starts to leaf out and then we get a hard freeze, with temperatures in the mid- to upper-20s or lower. The duration of the freeze would also be a factor in how much damage is done.

“Buds are kind of like a blanket,” he said. “The more those buds open, the more those blankets come off and the more potential damage to be done.”

Fruit trees like plums and peaches bloom really early. And while they have good winter resilience now, if those buds open, even temperatures that fall to 32 or 30 degrees could damage the fruit crop.

“That’s our fear — we are just warm and then either in March and April, we get one of those really extreme cold spells,” Patton said.

The average frost-free date for most of the Kansas City area is in early to mid-April, which is a little misleading because it’s a statistical average.

“It doesn’t mean that a frost will never happen after April 15,” he said. “It just means that in 50 percent of the years, there will be a frost after that day.”

It’s not until early May that the chance of a frost happening drops below 5 percent.

“We’re still back where there’s a 100 percent chance of a frost this early,” Patton said.

In the spring of 2007, there was an Easter freeze that did a lot of damage.

“We had a really early warm period in early March, and then it went down into the teens,” Patton said. “There were new shoots on plants about 4 to 5 inches long, hostas were up and growing, and it just turned all that into a mushy mess. It just froze.”

For the plants that survived, it took several months to recover.

“If we were guaranteed of staying above the upper 20s or 30s the rest of spring, hallelujah,” Patton said. “It’s that unexpected that always happened.”

With temperatures to return to seasonal levels this weekend, overnight lows might dip into the mid- to upper-20s.

“Even though things are ahead a couple of weeks, what has really kind of opened up now can tolerate some pretty cold temperatures,” Patton said. “We should be fine now.”

But if the warm weather continues allowing more plants and trees to come out of dormancy, the potential for damage increases.

The other concern right now is the dry winter Kansas City has faced so far. Patton suggests people start watering any relatively young plants, trees and shrubs that haven’t had a chance to develop a deep root system.

He suggested that people resist the urge to prune their trees for a couple weeks and to leave the lawnmowers in the garage. Instead, people should get out and enjoy the nice weather this weekend.

“Take it when you can get it, because you’re not going to be able to control it,” Patton said.

This story was originally published February 22, 2017 at 1:37 PM with the headline "KC’s early spring could lead to damaged plants if late frost, freeze strikes."