WENATCHEE, Wash. — Warm weather is pushing early bud development of fruit trees in Central Washington, lengthening the time of potential frost damage, which so far has been minimal.
Computer modeling of blossom degrees — an accumulation of daytime temperatures above 43 degrees since Jan. 1 — forecasts full bloom of Red Delicious apple trees for April 21 in Wenatchee. That’s six days ahead of the 30-year average.
The official declaration is made by Tim Smith, Washington State University Extension tree fruit specialist, when 60 percent of the king bloom, or center clusters, are fully open on the north side of three Red Delicious trees at the WSU Tree Fruit Research and Extension Center.
Full bloom of the Reds is the standard by which growers estimate the bloom of all varieties of fruit trees in the Wenatchee area and determine the timing of pesticides, chemical thinning and placement of bee hives for pollination.
In 91 years of records at the site, the earliest bloom was April 11, 1934, and the latest was May 16, 1922.
This year, apricots appeared in full bloom in Wenatchee on April 4. Cots were past bloom in the Tri-Cities by April 7 and peaches and nectarines were in mid-bloom, said David Douglas, president of Douglas Fruit Co., Pasco.
“Cherries should be in full bloom this week in the (Columbia) Basin,” he said. “It’s supposed to be 80 (degrees) today, so things will start happening.”
The day’s highs were 77 in Pasco and 73 in Wenatchee.
There’s been minor frost damage on cherries and cots, Douglas said.
Dan Plath, orchard manager at Washington Fruit and Produce Co., Yakima, said warm nights the last two weeks pushed buds the most.
“Fortunately, it’s been one of the most uneventful frost seasons I can remember, knock on wood,” Plath said.
Forecasts indicate it may be a light frost season, but there’s a month to go and it could turn bad if buds develop in the warmth and then get hit by a late frost, he said.
Earlier bloom can mean lower temperatures at bloom, which can create problems with fruit set and some thinning and size-enhancing sprays that are temperature-dependent, Plath said.