Ask a (local) master gardener about avoiding winter burn

Q: How do I take care of my broadleaf evergreens over the winter? I had quite a bit of winter burn last year and do not want to repeat it.  —M.D. Westhampton

A: The winter nip is certainly in the air this week!  We typically think of evergreens as not needing any overwinter care, so I am glad you asked this question. As the temperature dips consistently into freezing territory and below, as it looks to do this coming week, broadleaf evergreens benefit from some preventive care. 

Most winter plants will get some leaf browning/spotting due to moisture loss over the season from freezing winds. The winter burn you saw, though, is more severe. It is what happens to the leaves of broadleaf evergreens such as rhododendrons, azaleas, boxwood, euonymus, and holly when the roots of the plant go dormant, but then in late winter/early spring the sun warms things up sporadically causing the shrub to temporarily break its winter dormancy. 

While we humans love this brief sign of spring so we can momentarily shed our heavy coats, this awakening causes the broadleafs to want to make food. They try to kickstart the process by drawing water up from their roots, as they need water to make food through photosynthesis. When they attempt this while the soil is still frozen, however, there is no water available (it is all ice) and instead, the existing water in the leaves gets evaporated out with no new water to replace it. Without water in them, the leaves on rhododendrons, for example, curl up and turn brown, sometimes falling off. This makes for an unsightly plant come springtime, which none of us gardeners wants to see.

To minimize winter burn damage, research natural products like Wilt-Pruf by talking with your local nursery or garden center or checking on-line. These are products you can apply to the leaves and thereby create a protective barrier for them. Use any product you choose according to its manufacturer’s instructions. Always read the instructions before using any spray!

Do your shrubs grow in an open spot exposed to the winter wind? If so, they may also benefit from a burlap barrier, either putting burlap on stakes around the shrub or loosely tying it to the shrub itself.

I hope these suggestions help, M.D.!  It is good you are thinking ahead about your plant care. Thanks for asking a (local) master gardener!

Have a gardening dilemma? Please send questions, along with your name/initials and community, to the Western Massachusetts Master Gardener Association at AskAMasterGardener@wmmga.org. One question will be selected and answered per week.

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