Proper Mulching
Benefits of Proper Mulching

: Helps maintain soil moisture. Evaporation is reduced, and the
need for watering can be minimized.

: Helps control weeds. A 2- to 4-inch layer of mulch will reduce the
germination and growth of weeds.

: Mulch serves as nature’s insulating blanket. Mulch keeps soils
warmer in the winter and cooler in the summer.

: Many types of mulch can improve soil aeration, structure
(aggregation of soil particles), and drainage over time.

: Some mulches can improve soil fertility.

: A layer of mulch can inhibit certain plant diseases.

: Mulching around trees helps facilitate maintenance and can
reduce the likelihood of damage from “weed whackers” or the
dreaded “lawn mower blight.”

: Mulch can give planting beds a uniform, well-cared-for look
























Problems Associated with Improper Mulching

Deep mulch can lead to excess moisture in the root zone, which
can stress the plant and cause root rot.
Piling mulch against the trunk or stems of plants can stress stem
tissues and may lead to insect and disease problems.
Some mulches, especially those containing cut grass, can affect
soil pH. Continued use of certain mulches over long periods can
lead to micronutrient deficiencies or toxicities.
Mulch piled high against the trunks of young trees may create
habitats for rodents that chew the bark and can girdle the trees.
Thick blankets of fine mulch can become matted and may prevent
the penetration of water and air. In addition, a thick layer of fine
mulch can become like potting soil and may support weed growth.
Anaerobic “sour” mulch may give off pungent odors, and the
alcohols and organic acids that build up may be toxic to young
plants.


























Proper Mulching

It is clear that the choice of mulch and the method of application
can be important to the health of landscape plants. The following
are some guidelines to use when applying mulch.

Inspect plants and soil in the area to be mulched. Determine
whether drainage is adequate. Determine whether there are plants
that may be affected by the choice of mulch. Most commonly
available mulches work well in most landscapes. Some plants may
benefit from the use of a slightly acidifying mulch such as pine bark.
If mulch is already present, check the depth. Do not add mulch if
there is a sufficient layer in place. Rake the old mulch to break up
any matted layers and to refresh the appearance. Some landscape
maintenance companies spray mulch with a water-soluble,
vegetable-based dye to improve the appearance.
If mulch is piled against the stems or tree trunks, pull it back several
inches so that the base of the trunk and the root crown are exposed.
Organic mulches usually are preferred to inorganic materials due to
their soil-enhancing properties. If organic mulch is used, it should
be well aerated and, preferably, composted. Avoid sour-smelling
mulch.
Composted wood chips can make good mulch, especially when
they contain a blend of leaves, bark, and wood. Fresh wood chips
also may be used around established trees and shrubs. Avoid
using noncomposted wood chips that have been piled deeply
without exposure to oxygen.
For well-drained sites, apply a 2- to 4-inch layer of mulch. If there
are drainage problems, a thinner layer should be used. Avoid
placing mulch against the tree trunks. Place mulch out to the tree’s
drip line or beyond.
Remember: If the tree had a say in the matter, its entire root system
(which usually extends well beyond the drip line) would be mulched.
Proper Mulching