Mulching, How and why we use mulch with our trees and gardens in Milwaukee.
Homeowners and professional arborists depend on mulch in landscapes for several reasons. Functionally, mulches discourage weeds from growing, conserve moisture during drought periods, and allow better use of water by controlling runoff and increasing water-holding capacity of light, sandy soils. Mulches help maintain a uniform soil temperature. A 3- to 4-inch layer of mulch can add to the aesthetic value of a garden while protecting the base of trees from being injured by equipment, such as lawn mowers. Mulch rings also decrease competition from lawn grass. Lawn grass, especially when lush, robs trees of valuable nutrients and moisture.
Mulch rings should be no more than 3 to 4 inches in depth
and should not cover the bark of the tree trunk.
Many organic materials
can be used as a mulch. Bark mulches and wood chips are the two most
commonly used mulches in most of the country. In the south, pine needles
are included in that list.
Mulch can be applied
just about any time of the year when trees and shrubs are being planted.
The best time, however, to apply mulch in established bed areas would
be in mid-spring when the soil temperature has warmed up enough for
sufficient root growth. If applied earlier, the mulch will keep the soil
temperature lower and root growth could be delayed. Mulches should be
applied 2 to 3 or 4 inches in depth over relatively clean, weed-free
soils. Do not pile mulch more than 4 inches. Identify and eradicate the
weeds before the mulch is applied. Keep mulch pulled 12 inches back from
the tree trunk.
Incorrect Mulching: This mulch is piled
too high and too close to the tree trunk.
Most arborists consider
organic mulches as the most compatible with trees. There are, however,
several inorganic materials used as mulches. These include weed
barriers. Black plastic is sometimes used to discourage weeds, however
it interferes with the normal oxygen and water supply to the tree’s
roots. When the plastic is used, a very shallow root system is created
and during drought periods the plants may not withstand the stress.
It is recommended not to use black plastic around trees.
There are, however, several landscape fabric “mulches” available
that will function the same as plastic, but allow for normal water and
oxygen exchange. These materials, sometimes called geotextiles or weed barriers,
are placed on bare soil around trees and shrubs with mulches used on
top. There are many brands and types of materials from which to choose.
They have proven to be beneficial in discouraging weeds and conserving