We’ve been fortunate to have several mild winters in succession and, while I’m hoping for more of the same this year, there are no guarantees – even with global warming.
So, each autumn we’re faced with how and when to protect our plants – and the investment of resources, time and energy we’ve put into them. Life would be so much easier if we knew ahead of time what the winter would bring but because we don’t, there are some strategies you can use to prepare your plants as best as possible for the months ahead.
First, make sure all shrubs and trees go into the winter with a good, deep watering just before the soil freezes hard.
Fall-planted items – and any plants that are of dubious hardiness - should be well-mulched after the soil surface freezes to keep the soil from freezing deeply too early. This will allow roots extra time to get settled in. Light, sandy soils are more susceptible to freezing deeply than heavy soils so be especially vigilant to mulch vulnerable plants in sandy soil.
Some plants such as broadleaf evergreens – rhododendrons, hollies and euonymus, and some of the borderline-hardy needled evergreens, can suffer severe winter-burn when their roots are frozen and cannot replace leaf-moisture lost due to winds or thawing in bright winter sunshine. One way to protect susceptible plants is to spray them with an anti-desiccant such as ‘Wiltpruf’ or ‘Leaf Shield’ that will serve to prevent excessive moisture loss.
Some years ago, there were articles written about how these products don’t increase winter hardiness which is true, but they certainly do provide an extra edge to keep plants from winter burning. (I liken this to putting on moisturizer and sunscreen before skiing.) I’ve also found anti-desiccants helpful on Japanese maple trees in that they protect the fine, twiggy branches from drying out easily.
Anti-desiccants must be applied when daytime temperatures are still above freezing. Before applying to any plants, however, always check the product label to make sure it is recommended for the plants you wish to use it on.
Burlap or white tree wrap (N-sulate) can alternatively be used to achieve the same result as the anti-desiccant but, frankly, the effect created is not particularly pleasing. I believe strongly in the importance of landscaping with evergreens, and colorfully-twigged and berried shrubs to provide interest though all four seasons. Brown or white-wrapped ‘blobs’ in the landscape don’t quite fit that scenario!
If you need to wrap evergreens to keep branches from bending or breaking in heavy snowfalls, use black plastic netting instead. It’s inexpensive, easy to use and, visually, it virtually disappears, being effective without looking unsightly all winter.
By Harriet Hanna