Published on 08/30/06

Natural blanket keeps plants alive over winter

By Gary Wade
University of Georgia

In a few weeks, gold, red and yellow leaves will flame on tree branches across the state. And then they will drop. Instead of spending your fall dragging leaves to the curb, consider using them as a blanket – for your plants.

Winter is approaching, and your plants need a warm bed just as much as you do.

While the tops of landscape plants go dormant for the winter, roots don't have such luxury. They continue to grow all winter. Active growth means the roots can’t acclimate to cold and can easily be damaged if not provided extra insulation.

For instance, studies have shown that the roots of Southern magnolia can be killed around 25 degrees, while the roots of pyracantha and dwarf yaupon holly can be killed at 20 degrees.

Our soil seldom gets this cold, but who wants to take a chance when prevention is as easy as one-two-mulch?

One of the best winter antifreezes for the landscape is fall leaves. Three to five inches of leaves placed over the soil will keep plant roots toasty warm this winter.

The key to success when using leaves as mulch is to reduce their size by shredding them. Shredded leaves don't blow around like whole leaves.

If you don't have a shredder, simply place the leaves in small rows about one foot high and two feet wide. Then, with the lawn mower wheels in the highest setting, run over the row a time or two.

A bagging attachment or a nearby tarp can collect the shredded leaves, which make a fine-textured mulch.

Use shredded leaves as a mulch under trees, shrubs, annuals and perennials.

I've used fall leaves to overwinter begonias, petunias and lantana in my landscape. These plants will perennialize throughout most of Georgia if you provide them winter protection.

After the first killing frost, I cut them back to the ground, cover them with at least five inches of shredded leaves (more if you have them), then leave them undisturbed until the next April. With a well-established root system, the plants will usually come back better than before.

Fall leaves are also affordable insurance against damage to tender tropicals and prized roses.

When temperatures are forecast to drop into single digits, place a cylinder of chicken wire around tender plants. Make it two to three times wider than the plants and at least a foot or two taller. Fill the cylinder with leaves, packing them lightly and carefully to insure extra insulation.

Remove the cylinder and leaves when the weather warms above freezing.

Fall leaves chopped into the fall vegetable garden will become rich dark humus by next spring. And when leaves are added to the compost pile, you’ll be rewarded with black gold.

If you don't like the looks of leaves as a mulch, use them as a base under pine straw or bark mulch, reducing the amount of other mulch needed and saving you money.

Once you learn to appreciate fall leaves, you may be tempted to become a leaf marauder like me, traveling deserted city streets at night, collecting bags of leaves others have discarded at curbside.

I can't understand why anyone would let their leaves leave home.

Gary Wade is a Cooperative Extension horticulturist with the University of Georgia College of Agricultural and Environmental Sciences.