Mulch, styrofoam protect plants from winter kill, disease

October is here so it’s time to put the garden to bed for the long winter ahead. Besides last minute watering, weeding and cleanup and storing tools and accessories, attention must be given to adequately protect plants so that they come through the winter well. It is a good idea to protect both hardy plants and more tender specimens.

Although many gardeners clean off their perennial borders and cut back hardy roses in the fall, if you have experienced a lot of winter kill in the past, you might consider postponing this task until spring.

The old foliage will add protection to the plant roots and catch snow to ensure good snow cover.

The old stems will also trap leaves as they blow about in the fall, adding more protection. Some gardeners mulch their perennial borders with six centimetres of dead leaves each fall.

Just before freeze-up, water perennials, trees and shrubs well. Plants will survive the winter better if their root balls are moist instead of dry. This is particularly important for evergreens, which continue to transpire moisture all winter and need a good supply of moisture at their roots.

Try to add mulches after you water, not before, because wet mulch has far less insulating value than dry mulch. Mulches often can be kept dry by applying them late enough in the fall that precipitation falls as snow rather than rain. Early snow, however, often melts on a sunny autumn day and soaks the mulch.

Mulches such as dry leaves and peat moss can be kept dry by covering them with a waterproof cover such as plastic or Styrofoam. When applying the cover, ensure that there is some air circulation by leaving a gap around the bottom to let air in but keep rain out.

Tea roses, hydrangeas and other tender plants can be covered with mulch and then Styrofoam cones. They offer insulating value and keep the mulch inside them dry.

Before applying mulch, many gardeners pour dry soil over the plants. Don’t make the mistake of simply raking surrounding soil up onto the plants as this will decrease the soil cover over the plants’ roots and lessen their chance of survival.

If you have evergreen shrubs with a southern exposure or planted against a wall that reflects a lot of sunlight, consider erecting burlap barriers to block the rays of the sun.

The burlap should be fastened securely to sturdy stakes and not touch the foliage.

Make sure the barriers are high enough to protect the tops of the shrubs from the sun’s rays. Keep them in place until after the snow has melted and the soil has thawed.

To protect my Oriental lilies, which are planted in a square patch to facilitate easy protection, I put on about 15 centimetres of dry soil (I use compost) and then I cover that with about 40 cm of dry leaves. Over this, I place a piece of heavy plastic tied down around the edge to allow some air to get under it to prevent moisture buildup.

Last year, I streamlined the process by putting the leaves inside a large plastic mattress bag and placing the bag on top of the compost.

I guessed enough air could get under the bag to prevent moisture buildup. You too will devise methods of protecting your plants that are both simple and effective, but be sure to do this job before freeze-up and before the snow comes to stay.

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