As our reluctant spring weather may finally arrive, and with a little sunshine we will find ourselves outside enjoying our landscapes more and more. Behind us was a winter loaded with snow and colder than recent memory temperatures. School children rejoiced with extra days of school because wise superintendents thought the better of running buses at -5F bus stop temperatures. Although we are able to protect our children, our plants tucked into our landscapes may not have been so fortunate.
As the temperatures warm, our landscapes will come alive with new growth, bright flowers and bold foliage. It will be then that we begin to recognize the impact of the winter season. Winter burn is one of the culprits we're prominently seeing in the St. Louis area.
Impacts to evergreen and late flowering summer shrubs will be the greatest.
Evergreens experience a winter drought stress as a result of moisture literally being frozen in the ground- thus the plants cannot take up the moisture they need for normal transpiration. The most obvious damage, winter burn, will show up on formerly tender new growth from late fall that did not have a chance to harden off prior to the cold temperatures.
These brown, gray, light yellow leaves will soon be replaced with new growth. Having said that, foundation evergreens like Azaleas, Rhododendrons, Hollies, Junipers, Boxwoods, Yews and Arborvitae will benefit from a good watering this very weekend. Even with rain in the forecast, a little extra water helps to insure plant vigor.
Late flowering shrubs, Crape Myrtle, Rose of Sharon, Caryopteris, Laurels, Butterfly Bush and others tend to be on the Northern end of their growing range. We all know that St Louis sits in a transition zone for weather – occupying the 5-6 hardiness zone designation.
Will my plants recover from winter burn?
Mild winters tend be more typical for the zone 6 weather. Harsh St. Louis winters, like this past one, tend to push into the zone 5 weather. The resulting impact of below zero degree temperatures can be fatal to some of these flowering shrubs. It would not be uncommon for some of these shrubs to show no new signs of growth until May.
The real lesson here is one of patience. Micro climates, winter protection, and plant placement all enter into the mix in determining the rebound of the late summer show stoppers. In other words, Mother Nature may have chosen to prune your 48” tall Crape Myrtle down to 12”. Have faith my fellow gardeners, this too shall pass, the Crape Myrtle will live to see its past 48” glory regained!
If you need help diagnosing winter burn and whether or not your plants can be saved, please contact Dowco!