From Rosie Lerner, Purdue University Consumer Horticulturist
Magnolia flower freeze damage. Photo courtesy Purdue University.
As most gardeners have marveled, we’re having one of the earliest “spring” seasons this year, with woody plants herbaceous perennials three to six weeks ahead of “normal.”
And then, perhaps inevitably, “normal” spring frost and freeze visited. Being so much further along in their development, plants are quite vulnerable to damage.
Note that freeze incidents are normal for this time of year. What is abnormal is the earliness of development, leaving the plants exceptionally vulnerable to freeze.
The good news is that woody plants, in most cases, will outgrow the damage.
Oak leaf freeze damage. Photo courtesy Purdue University.
Home fruit-growers have reason to be concerned: At 28 F, you can expect a 10-percent loss of flowers and young developing fruit. However, at 25 degrees F, that loss increases to 90 percent! In the Lafayette area, the temps hit 27 to 28 degrees F the morning of April 12, followed by 24 to 25 degrees F the morning of April 13 — a double whammy.
Bud counts were exceptionally high until the freeze, so in some cases, even just 10 percent retained fruit might still be a decent crop on our tree fruits. Grapes may also still have ability to crop on shoots that have yet to emerge. Strawberries are a bit easier to protect through frost and freeze, but only if you took measures, such as using floating row covers, recovering with straw, etc.
However, it is only mid April, and additional frosts and freezes are still possible.
Bottom line is that unless it is already a complete loss, you won’t really know the rest of the story for quite a few more weeks.
Peach bud freeze injury. Photo courtesy Purdue University
It is easy to check fruit buds for damage by cutting open the bud and looking for dark brown or black centers. Purdue Extension fruit specialists put together these videos to help you assess the spring freeze damage on:
For ornamental trees and shrubs, plant response has been quite varied, depending on species, location and, of course, temperature and duration of that temperature.
Susceptible plants may have wilted leaves, brown or black necrotic spots on leaves, or perhaps dieback of entire twigs. Plants that were in bloom likely have brown petals or dropped flowers entirely. Here are some links to articles from previous spring freezes that will give more information.
