Extension Service Garden Hints

Mulch perennials for winter protection

EUGENE - Autumn is a great time to mulch around your ornamental shrubs, fruiting trees and vines and perennial flowers, before winter sinks its icy talons into your home landscape.

Whether you choose shredded bark, manure, conifer boughs, composted mint hay, well-rotted sawdust, composted leaves or thoroughly dry grass clippings, an organic mulch will help protect perennial roots, keep weeds down, prevent nutrient loss and help insulate plants from the cold, explained Pat Patterson, Oregon State University Master Gardener program assistant.

Shrubs like roses, azaleas, rhododendrons and hydrangeas can really benefit from low-nutrient mulch. Flowers such as lilies and dahlias, and spring bulbs like tulips and daffodils will do better with this type of mulching also.

Blueberry bushes and lingonberries send out roots along the soil surface, and they appreciate a thick layer of well-rotted sawdust. Caneberries will benefit from organic mulches such as composted manure. Rhubarb and asparagus beds do best covered with seed-free straw-filled manure. But be aware that some mulches may have weed seed. You can compost the manure for one year then use it as mulch to alleviate the weed problem. Dormant vegetable beds can benefit from a six-inch blanket of manure and leaves.

Avoid mulching with hay, especially ryegrass straw unless it is thoroughly composted. Otherwise, it has too many seeds that will eventually sprout and will create a serious weed problem.

Don't use grass clippings from a lawn treated with a weed-and-feed preparation. The herbicide will stay in the clippings and can damage your shrubs.

When you mulch around tree trunks, make sure that you do not place the mulch up against the bark. Mulch against tree bark encourages crown rot and allows easy access for mice, which might girdle the bark around the base of the tree.

By: Carol Savonen
Source: Pat Patterson, Ross Penhallegon

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