|May 12, 2014 snow on cherry fruit buds|
At this stage of tree fruit bud development (full bloom to petal fall), we can expect 10 percent bud kill at 28 degrees F and 90 percent bud kill at 25 degrees F. This is with a 30 minute exposure and it doesn't matter if it is apples, cherries or peaches. European plums are somewhat hardier and it will have to go down to 23 degrees F to reach an expected 90 percent fruit bud kill and similarly to 24 degrees F for pears.
Cold damage to developing buds of fruit trees can be minimized by planting near the tops of slopes where cold air drains to lower levels and by avoiding blockages (such as fences) to cold air draining away .
Good yields of tree fruit may only be achieved in 2 or 3 years out of five on Colorado's Front Range. This is looking like it could be one of those off years.
Photo credit: Cherry fruit buds in May 12, 2014 snow - Carl Wilson