Franklin County

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Purdue Extension: Expert Resources for COVID-19

The Big Chill

January 22, 2018
fozen trees

Mother Nature has put garden activity on ice for now, but most hardy landscape plants can cope with the extreme weather.

When winter temperatures dip below zero and winds howl across the prairie, gardeners may worry that their trees and shrubs are taking a beating. No need for doom and gloom yet - most hardy landscape and orchard plants are reasonably able to cope with most of our winters, including our recent polar vortex.

Many factors influence plant injury, including plant species and cultivars, degree of plant dormancy, and overall plant health. Other factors include how low the temperature goes, how long it stays there, and how well-acclimated plants are at the time of the cold snap.

Much of Indiana endured numerous days of near- or below-zero temperatures and high winds. While it is too soon to know how much damage to expect, the good news is that plants should have been fully dormant prior to worst of the weather. Snow cover helps by providing considerable insulation.

Severe lows coupled with high winds may cause some dieback of twigs and winter burn on ornamentals, especially evergreens. Broad-leaved evergreens are the most susceptible. Winter desiccation injury occurs when the roots can't absorb water fast enough to keep up with moisture lost by the foliage (through transpiration). This occurs mainly on sunny days, especially if it is windy and the soil water is frozen - the plant can't absorb it - or if water is in short supply. Injury appears as brown leaf margins or needle tips at the onset of warm weather

Generally, flower buds are more sensitive to cold than leaf buds, so flower buds on some fruit species such as peaches, nectarines, and blackberries have likely been damaged. However, it is likely that some flower buds will survive, enough for at least a partial crop. Grapes may also have significant bud loss, particularly on more tender cultivars. Species or cultivars that are marginally hardy will likely suffer dieback, or possibly death, but this may not be obvious until spring thaw or later. You will want to delay major pruning until after you can assess winter damage.

There is still plenty more winter to endure before we will know the status of our plants. There isn't anything you can do to control the weather, so stay safe and warm. and dream of warmer days to come!


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