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Holly Winter burn

Winter Damage: What is it and What Can I do About it?

We’ve faced some brutal cold spells this winter and are already seeing the damage to some of our more vulnerable landscape plants. With winter damage, plants typically have dry, brittle and brown leaves, and many people assume these plants are dead. The good news is that plants are amazing in their resiliency and more often than not they will put out new growth and fully recover this spring. If you have plants that appear to have winter damage, resist the urge to dig them up. We recommend leaving them in the ground to give them every opportunity to live and thrive this spring.

Winter Damage, Nandina

Identifying Vulnerable Plants

The plants most vulnerable to winter damage are:

  • Broadleaf evergreens
  • Those that have been planted in the past year
  • Container plants
  • Any plant that is at the boundary of its viable gardening zone

Examples of vulnerable plants include gardenia, camellia, southern magnolia, nandina, laurels, boxwood, hollies, figs, hydrangea and rosemary. Container plants are especially susceptible to winter damage since the roots are adapted to growing in the sheltered soil environment. With a limited amount of soil to insulate and protect the roots, they may freeze and die. Recently planted broadleaf evergreens are vulnerable to winter damage because they continue to pump water through their leaves year-round (this process is called transpiration). During extended cold spells, water in the soil can freeze and become unavailable to the plant. This becomes more problematic when we do not get sufficient snow or rain to replenish the soil moisture. Windy conditions will also increase transpiration rates causing the foliage to dry and turn brown. Imagine you planted an evergreen holly this summer. It is still in the process of establishing a full root system, therefore its ability to absorb water from the soil is limited. This year (2017-18) winter arrived early with very cold, dry and windy conditions. With this combination of stresses, it is likely this plant will experience some amount of damage.

Azalea, Winter Damage

What Can You do to Mitigate Winter Damage?

  1. Check the soil moisture throughout your landscape with special attention to vulnerable plants. If you discover they are dry, take time to water them on a day when temperatures are above 40 degrees F.
  2. Be patient and wait for signs of recovery this spring. Most plants will show signs of recovery in April and May, however, others may be delayed until June. Resist the urge to remove or start pruning until we know the extent of injury.
  3. After you see new growth beginning to emerge and you are able to determine the extent of injury, prune to remove dead branches. Avoid removing live, green growth as the plant needs leaves to produce food and aid in recovery.
  4. As the new growth begins to emerge, fertilize with a good quality, slow release plant food to speed up the recovery process. See our staff for specific fertilizer recommendations.
Winter Damage, Juniper

We are here to help!

There are many factors that influence the extent and effects of winter damage your plants will experience. Exposure to wind, temperature and moisture extremes, plant species, root establishment, pruning, mulching and watering practices all will guide our decisions in how best to assist our plants through recovery. The more information you provide us, the better we are able to help you. Photographs are useful in determining the pattern and extent of winter injury, but don’t tell the whole story. We need plant samples to examine and determine if the buds are viable. Bring 6” to 12” twigs, along with photos of the plants in question, to the Plant Clinic at any of our three Merrifield Garden Center locations for consultation and evaluation with our plant specialists. Don’t let the winter get you down! Lilacs, cherries and spring bulbs are just a few of the plants that thrive following a cold winter. There will be plenty of blooms to reward us this spring and we’ll be here to help make the most out of your garden.

Snow Landscape

Ready or Not, Here Snow Comes

David Yost, Merrifield Plant Specialist

It was Christmas, 69 degrees, sunny and somehow we had managed to escape winter. Two weeks ago, I still had customers purchasing grass seed! Now with freezing weather and a major snowstorm on the way, Christmas seems like the good ol’ days and winter has arrived.

I’ve been a gardener for most of my life, but since “Snowmageddon 2010”, I’ve been especially attuned to how severe winter weather affects our gardens. You may recall that during this storm 20 inches of snow blanketed the Washington, D.C. region, causing power outages, stranded travelers, etc.

We all saw how the branching habit of evergreens, such as Leyland Cypress, collected the snow and toppled over, but the ‘Green Giant’ arborvitae shed the snow and remained upright. We also saw how trees with brittle wood and/or weak branching structure split, broke and suffered major damage while trees that had been pruned to maintain structural integrity escaped injury.

Tree - and car! - damaged by heavy snow.

A couple of years later, we experienced a very dry winter with little snow and saw broadleaf evergreens, especially Japanese hollies, nandina, magnolias and camellias turn brown and shed their leaves the following spring because of winter desiccation. And then the past couple of winters we have seen rosemary, gardenias, figs and other plants killed or damaged by extremely cold temperatures.

So what have I learned and how does this apply to the approaching storm?

  1. Snow is good for the garden! Snow acts as a warm blanket, keeping the temperature at a cozy 32 degrees and sheltering your plants from the drying winds. As it melts, the snow gradually replenishes moisture in the soil.
  2. Pruning works! Woody plants that have been pruned to maintain a sound branch structure will usually be able to support the weight of even a heavy snowstorm with little to no damage.
  3. Remove heavy snow from evergreens. Gently brush it off with a broom before it accumulates to the point where it is breaking branches or pulling the plants to the ground.
  4. Follow the instructions on ice melt products. All of these products, even those labeled as natural and/or safe, contain salts that will damage your plants if you apply too much.

    Shrubs damaged by ice melt.

    Shrubs damaged by ice melt.

  5. If your plants do get damaged, be patient and allow them time to recover in the spring. Resist the urge to prune or remove plants until you know they are dead. Some plants may not show signs of recovery until as late as June.

If you need help getting your garden prepared for winter, we are ready to help with questions, ice melt and snow shovels to keep you and your garden comfortable through the storm.