Tip of the Week — 11/17/08

Posted in Gardening Tips on November 17 2008, by Sonia Uyterhoeven

Protecting Plants
Sonia Uyterhoeven is Gardener for Public Education at The New York Botanical Garden.

It is time to think about protecting your plants for the cold winter months. With roses, here we simply “hill them up” with 6-8 inches of mulch. After the temperature drops and the roses go dormant, usually in late November to early December, we pile a small mound of mulch around the base of the plant. This acts as a winter parka, protecting the base of the rose from freezing temperatures. Once the weather warms in March, we pull away the mulch and start preparing for spring.

Some of your shrubs, such as the bigleaf hydrangeas  (Hydrangea macrophylla)—mophead and lacecap types—flower on old wood. This means that the plant develops its flower buds on the previous year’s growth. Sometimes cold or variable winter weather (changing from warm to cold) can disrupt the flowering, killing off potential buds for the following season. One way to protect your hydrangeas that are situated in an exposed area and at the mercy of the elements is to provide a wind break. Place 5 or 6 stakes around the plant and wrap with burlap. The top can be kept open so that snow (nature’s greatest natural insulator) can fall in.

If it is containers that you are concerned about, the simplest answer is Bubble Wrap. Garden centers sometimes sell a horticultural version that has a silver foil lining with Bubble Wrap inside. Insulate hardy containers once they freeze; with half-hardy containers, insulate before they freeze. Wrap the container with Bubble Wrap and secure with garden twine. If possible, tie the Bubble Wrap over the top of the container, pulling it up around the base of the plants so that the soil in the container is covered. This will help protect it from the freezing and thawing cycle that usually happens in February. If your container is not hardy, place it in an unheated garage so that it can go dormant for the winter.