Plants in a cold frame outside
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How to Protect Semi-Hardy Plants

We are blessed in the Northwest for many reasons and one of the biggest is our ability to grow a large variety of plants, including vibrant exotics. There are many plants that stretch the limits of being tolerant of our climate and love our warm and dry summers. When it cools down and the drizzle picks up speed, the tender or semi-hardy plants that we introduced to our gardens may need some extra attention to get them through the next few months.

To start, get to know your plants needs. Some plants may require being dug up and moved to a drier and more sheltered location (like Geraniums or Dahlia tubers). Or they may only need mulch around their root system or even around the base if they have been grafted (like roses for example). Or they may need to be wrapped to keep the cold wind from drying out their stems or even want the protection of a cold frame (artichoke). Research individual winter protection needs for your plant or call the Garden Hotline for suggestions.

Wrapping your plants can not only protect plants from biting winds; if built with a sloping top a structure can ward off snow and prevent breakage of limbs. An easy, low cost way to protect plants is to align several bamboo stakes vertically around the plant. Put the stakes firmly in the soil and attach all above ground ends to each other. Wrap the pole structure with burlap or Reemay and tie at the top and bottom with twine. This solution is also very easy to put up in a rush of an impending snowstorm.

Or for plants like Artichokes or a small Bay tree, you can wrap the plant with reemay or burlap as well as mulch the crown area with composted mulch. Or you can even construct a miniature greenhouse or cloche over precious plants in order to protect their tender stems and roots. Two old windows leaning into each other or even an dry cleaning bag over tomato cage can make a fine “greenhouse”. And what a great use for a tomato cage in the off season!

If your plants are in pots already then it is easier to move them to a warmer or more protected area. For example, if you want to preserve an annual geranium or a fuchsia, you can bring them into an unheated dark and dry place such as a basement or a garage. If you don’t have either of those options, it may work to bring the containers up next to the house under the eaves and cover them with a tarp or other material that will keep the plants from getting too much light. Generally, the area under the eaves is a dry spot. Make sure when overwintering geraniums and fuchsias that they do not stay too wet through the winter.

One of the biggest reasons that plants don’t make it through the winter is from drying out quickly or being overwatered. There is a delicate balance in the moisture levels for overwintering plants in other words. If you are bringing a pot into a covered area then you want to water it lightly about 1x month. If your pots are outdoors, then you want to keep the pots from getting too wet, especially if under an eave you may want to gently cover the pots to keep out excess rain.

Whatever your plant needs, the time to protect them usually starts in mid-September and by early November your plants should be snug and you can avoid leaving them out in the cold. You will also be ready to jump start your garden at the first sign of warm weather!