Reasons are many to mulch a garden
Q. Should I be mulching my garden, trees and plants?
A. If you want to conserve soil moisture, keep down weeds, reduce soil erosion and keep plant roots cool this summer, as well as provide protection over the winter, then the answer is "Yes" to mulching.
In essence, mulches help simplify landscape care by providing plants, trees and shrubs with a covering of protective material at their growing base. Many materials, both organic and inorganic, can be used for mulch. So how do you make the best selection for your needs? Start to think about how you will use it. Will it be a spring mulch, summer mulch or winter mulch? Generally, mulch can be applied any time of the year.
Mulch applied in early spring can help you get ahead of weed seeds by creating conditions that are unfavorable for their germination, and by providing a barrier for emerging weeds. Those weeds that do find their way through the mulch are easier to spot and will be easier to pull because the soil below stays moist.
However, if you have newly planted vegetation, mid-spring after the soil has warmed can be a good time to apply mulch. If you apply it while soil temperatures are low, plant growth may be inhibited. As spring changes to summer, you will find that in addition to reducing weeds and moderating soil temperatures, mulch helps to maintain moisture around your plants by reducing evaporation.
When heavy summer rainfalls occur, a layer of mulch helps decrease soil erosion by slowing water infiltration. Mulch applied in late fall and early winter will help provide protection from severe winter temperatures and frost heaving. Perennials and sensitive shrubs and flowers will benefit from the insulation provided by mulch laid down before the winter blasts arrive.
Your next decision will be to decide between organic and inorganic mulch.
Organic mulches include bark, wood chips, sawdust, straw, pine straw, shredded leaves and newspaper. Over time, these will decompose and turn into soil, adding organic matter, helping with moisture retention and providing nutrients for healthier plants. Because organic mulches decompose, you will need to replenish them from time to time.
Inorganic mulches such as crushed stone, gravel, volcanic rock, plastics and fabric mulches of polypropylene or polyester, tend to stay in place and don't harbor weed seeds. However, their greatest disadvantage is that they do not contribute organic matter to the soil. Stone mulches are more or less permanent, and when leaves, twigs, and other debris fall into rock mulches they can be tricky to remove along with giving the mulch an unattractive look.
Assuming you choose an organic mulch, how much should you use? You should spread 2 to 3 inches of mulch around the base of trees and shrubs. If located in a lawn, create a wide mulch ring, extending 3 to 6 feet from the trunk of each tree or large shrub. Pull at least an inch of mulch away from the trunk, and don't let it accumulate to depths greater than 4 inches.
You want to avoid piling mulch around tree bases in the shape of a volcano or pyramid to prevent suffocation of the tree. Mulch applied in this manner can ultimately cause the tree to decline.
Flower beds and borders should be mulched uniformly and in their entirety with an application of up to 3 inches of mulch. Actually, 1 to 2 inches will be sufficient around perennials, just be sure to pull mulch away from plant stems. Check for bare spots as these areas will be prone to rapid weed development.
- Mary Moisand
• Provided by Master Gardeners through the Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines, and University of Illinois Extension, North Cook Branch Office, Arlington Heights. Call (847) 298-3502 Monday, Wednesday and Saturday or (847) 201-4176, ext. 14, on Fridays.