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Using Mulch in Your Garden

Posted June 10, 2008 4:56 p.m. EDT
Updated June 10, 2008 5:25 p.m. EDT

Using Mulch in Your Garden

Nature has a simple and effective process for feeding and enriching the earth. When plants die or drop their leaves, the organic matter decomposes and returns nutrients to the soil. During the winter, this layer of organic matter protects seeds from the cold, and in the spring it holds in moisture to encourage seed germination. If the layer is thick enough, it will discourage new growth and protect established plants.

Gardeners have taken this natural process and turned it into the concept of “mulching” where a thick layer of organic matter is applied to planting beds and gardens.

Mulching helps the garden by providing:

  • Weed control
  • Soil enrichment
  • Moisture retention
  • Visual appeal

Types of Mulch

Mulch is both functional and decorative, with many different types available. When choosing mulch, consider the density and texture relative to the plants in your garden. Tender seedlings will have a hard time pushing through a thick layer of coarse mulch while large areas around trees and shrubs may benefit from a heavy weed-preventative barrier. While your choice of mulching material should primarily be based on its purpose, it’s also a matter of taste and budget. Some popular options include:

Organic Mulches that Break Down in One Season

  • Leaves: While readily available, uncomposted leaves are susceptible to blowing winds when dry and can pack down tightly when wet. Perfect for natural areas, they work best in formal gardens when composted first.
  • Grass Clippings: Plentiful during the mowing season, lawn clippings provide great soil amendment but may look messy until they begin to break down.
  • Compost: Compost packs a double punch as both mulch and an excellent organic fertilizer.
  • Paper: A layer of old newspapers work great as a weed barrier underneath mulch or straw. Try to use papers with biodegradable inks. Shredded waste paper may also be used.
  • Hay and Straw: Often used for newly seeded lawns and vegetable gardens since they break down quickly. Hay and straw often contain seeds that may sprout.
  • Less common (but effective) one-season organic mulches: Shredded corn stalks, manure, peat moss, and rice hulls.

Organic Mulches that Last More than One Season

  • Wood: The different varieties of mulch made from ground up trees ranges from shredded and stringy to chipped and chunky. Chipped cedar mulch is both attractive and aromatic. Wood mulches come in single- double- and triple-ground, with the price increasing each time it goes through the grinder. For an inexpensive basic mixed ground mulch, check your local landfill—many cities collect and grind lawn and tree waste, then sell it for as little as $5 per pickup load.
  • Bark: Beautiful and durable, bark nuggets have the disadvantage of drifting out of unedged beds, especially in a heavy rain. While relatively expensive, bark can be easily purchased in convenient lightweight bags and provides a nice finished look.
  • Pine Straw: Acid-loving plants love pine straw. Longer needles last longer than shorter ones. In areas with a lot of foot traffic, pine needles tend to break down quickly.
  • Dyed Mulch: Many shredded wood varieties of mulch are now being dyed every color of the rainbow. So if you’ve always wanted the color of your mulch to reflect your favorite sports team, you just might be in luck.
  • Other multi-season organic mulches: Seed and nut hulls, cocoa bean hulls, corn cobs, and sawdust.

Inorganic Mulch

  • Rubber: Often manufactured to look like wood or bark, recycled rubber mulches are commonly used in playgrounds and walkways. Rubber mulch is the topic of debate among environmentalists, as the benefits of recycling weigh against the potential for off-gassing of toxic chemicals into the air and ground water.
  • Rock: Stone, gravel, and crushed rock are highly resistant to wind and maintain their appearance for years. Since rock absorbs heat, it often gives gardens a parched appearance.

Applying Mulch

Spread mulch to a depth of 2” to 4” and keep it back slightly from stems and trunks to avoid smothering the plants. Avoid a “volcano” effect around tree trunks—trees grow their roots to varied and specialized depths and can be sabotaged by an extremely thick layer of mulch.

Beautifying Your Garden with Mulch

In designing your garden, think of mulch as the elegant background that allows your ornamental plants to show their stuff. Mulching not only makes mowing easier around trees but also calls attention to attractive bark and trunk shapes. For a balanced appearance around small ornamental trees, consider making the mulch ring the same diameter as the treetop.

Mulch can also be used to set off an area in a pleasing shape and act as a design feature in its own right. The mulched area serves to:

1. Eliminate the need to grow grass in a shady area.
2. Accentuate the gorgeous Japanese maple tree.
3. Provide a shapely curve in the overall lawn design.

Also consider using more then one type of mulch for design purposes. River stones can be used as an edging with shredded wood mulch around the plants themselves. While river stones often appear white or gray when dry, they can display beautiful colors when wet.

Whatever your design or purpose, your plants will be protected from extreme temperatures, weeds, and short dry spells by a protective layer of mulch.