How Did Your Plants Fare This Winter?

With lawns greening up, we’ll soon take that first really observant stroll through the home landscape and conduct our first lawn mowing. Did any plants get damaged over the winter? Is that even possible, given the mild winter we had?

As Lee Corso of ESPN always said, “Not so fast, my friend!” You might remember that extremely cold snap we had in late December. Preceded by an extended fall season, that dramatic temperature drop may have caused damage to some landscape plants.

Kyle Daniel, Purdue Nursery & Landscape Outreach Specialist, wrote an article in Purdue Landscape Report about winter injury.

“There’s ongoing evidence of damage across the Midwest from the late/long fall and extreme cold that was experienced in mid-late December,” he said. “We’ve observed some perennial evergreens, i.e. American holly, Meserve holly, and skip laurel damaged or killed during this winter, especially in southern parts of the Midwest.” He added that some deciduous trees have significant bark cracking.

“Though these plants are hardy well below the temperatures that were experienced, the maximum dormancy wasn’t yet reached by plants due to the warm temperatures so late into the winter season,” he said. “The dormancy process in plants is a complicated series of internal events caused by external events, that allow perennial plants to protect themselves during environmental changes, such as winter.”

Daniel said we could expect the following in the coming few weeks:

• As bud break begins, marginally cold hardy plants may have dead branches.
• If root damage has occurred, bud break may occur normally, but defoliation will follow due to a reduction in the ability to uptake water.
• If possible, wait to prune until after bud break so that dead branches can be removed.
• Early bud break followed by low temperatures will increase the chances of late frost/freeze damage to plants and most likely freeze blooms.
• Plants that have experienced damage from the winter will need to be watched carefully through this growing season to prevent other stresses, including drought.

Daniel mentioned bark cracking in trees in the aforementioned article. In a separate article, Daniel said that one of the most common types of bark cracking is termed Southwest injury. “Southwest injury occurs during the winter months on the lower section of the trunk on the southwest side,” he said. “This happens when there is a sudden temperature drop…usually this occurs on thin-barked trees, such as Acer spp., Cercis spp., Malus spp., and others.” (For reference, the genera referred to are maples, redbuds, and apples/crabapples.)

Find Daniel’s referenced article at https://www.purduelandscapereport.org/article/cold-injury-during-a-very-mild-winter/.