Are you overindulging in mulch? Since mulch has come to replace landscaping stones in suburban yards, many people are going overboard with it, thinking more about how it looks rather than how it is supposed to function. Shredded wood, wood chips or leaf mulch can all help keep in moisture and inhibit weed growth, but too much can be destructive to smaller plants, as well as bushes and trees.
Especially in city lots, soils can be depleted of helpful nutrients. Mulch, whether wood or leaf mulch, helps add nutrients back into the soil as it decays. If leaves drop in your yard naturally in the fall, make your own leaf mulch by raking the leaves together in a back corner and letting them turn into compost over the winter. (If, last autumn, you failed to rake before the first snowfall, you can rake the leaves together this spring and shred them by running over them with the lawn mower.)
Once the snow is gone from yard beds and the soil has dried out somewhat, take a wire rake or garden fork and stir up, but do not remove, the existing mulch, before adding another layer. Don't decide it looks bad and rake it off - it's supposed to decay. Aerating it will keep it from forming a tough layer or "crust," which will result in water running off instead of soaking in. Two to three inches of mulch is all that's necessary. Add new mulch as perennials begin to appear, and do not add so much as to tamp down budding plants.
Do not pile too much mulch at the base of trees. Avoid a situation where moist mulch is in contact with bark. Too much mulch makes water run off and away from the tree. Keep mulch 3-4 inches away from the base of a tree or visible roots.
If you do want to top off your mulch, the city of Madison offers free shredded wood, produced from tree maintenance and curbside pickup. Mulch is available from on the east side at the parking lot at Sycamore Park (across from the brush deposit facility at 4602 Sycamore Ave. On the west side, Garner Park and Elver Park. Mulch can also be picked up at the Brush Processing Center at 121 E. Olin Ave, at 7:30 a.m.-2:30 p.m. Monday through Friday (608-266-4911).
Another inexpensive mulch option is Olbrich Gardens leaf mulch, made from leaves collected by the city of Madison in the fall and composted throughout the winter. Come spring, they are double-shredded. This mulch works for most yard and garden applications, including vegetable gardens. Leaf mulch also helps in reducing weeds, retaining moisture, adding nutrients to the soil and inhibiting erosion. Olbrich leaf mulch has a neutral pH. Buying it also benefits the city, as the leaves are reused rather than hauled away.
Olbrich sells the leaf mulch for $6.50 a bag; each covers a 35-square-foot area (depth of 2-3 inches).
Used coffee grounds also make a good mulch or an addition to the compost bin. Coffee is acidic (with a pH 3.0-5.0), so coffee grounds are good for mulching plants that need acid amendments to the soil, such as rhododendrons. Grounds are also good in the vegetable garden. When dumping the grounds into your compost, the mixing with other household and yard matter will neutralize the acidity.
Some coffee shops make their grounds available to customers; call your favorite shop and ask.
Recycled rubber tire mulch is ecologically useful in that it provides a use for used tires. It's useless as a soil amendment. As a mulch, it can be used in instances where you don't want the mulch to decay soon or don't need to improve the soil. It will inhibit weed growth and drains rather than creates runoff and is most often found as a shock absorber in play areas. It's also useful in fenced backyards where dogs have made a dirt track along favored squirrel-chasing paths. It's not always easy to find, though. Midwest Decorative Stone in Madison (608-273-9787) sells it in 2-cubic-foot bags.
Lawn clippings can be used for mulching the garden. Do not apply when wet - wet grass will form a mat. Only untreated lawn clippings should be used (no herbicides). Grass clippings will create a layer of protection for vegetables that grow on the ground, too, inhibiting mold or rot.
Cocoa bean mulch, a popular look in landscaping, can smell terrific, but avoid it if you have dogs. If eaten, it can make the dog ill.
Ground cover plants such as pachysandra can also function as mulch.