ACES Publications

Alabama Smart Yards

CHAPTER FIVE: MULCHING

Mulch Facts
Guidelines for Using Mulch
How Much to Buy
Using Yard Waste as Mulch

MULCH FACTS

A mulch layer around trees, shrubs, and planted beds, and the covering of bare ground with mulch provides many benefits. In areas that are difficult to mow, irrigate or otherwise maintain, use mulch to replace turf or groundcovers. Also consider placing mulch in shady areas where plants don't grow well.

  • Organic mulch materials improve soil fertility as they decompose
    Organic mulches include bark materials, pine needles, compost, and paper. Over time, many types of mulch improve soil aeration, structure and drainage.
  • Mulch buffers soil temperature
    keeping soils warmer in winter and cooler in summer.
  • Mulch helps maintain soil moisture by reducing evaporation
    A layer of mulch also minimizes water needs for established plants.
  • Fresh mulch inhibits weed seed germination and growth
    A mulch layer can inhibit certain plant diseases.
  • Mulch around trees and shrubs (not against the trunk) eases maintenance
    and reduces the likelihood of damage from string trimmers.
  • Mulch gives a neat and uniform appearance
    to planting beds adding a contrast of color and texture that complements plantings.
  • Fine textured mulches that mat together decrease erosion

GUIDELINES FOR USING MULCH

Follow these tips when adding mulch to your landscape:

  • For well drained sites, apply a 2 to 3" layer
    (after settling) of mulch around trees, shrubs and bedding plants. Coarse materials, such as pine nuggets, may be applied to a depth of 4", but don't allow mulch to accumulate to a greater depth. Do not add mulch if there is a sufficient layer already in place (2" to 3").
  • Avoid more than 1" of mulch on a newly planted rootball or shrub Too much can cause drought stress to new plants because the mulch intercepts water meant for the roots.
  • Resist "Volcano mulching"
    as it hinders oxygen exchange to roots which stresses the plant causing root rot. If much is piled against the trunk, uncover the base of the trunk and the root flare as this mulch holds moisture.
too much mulch

Stems and trunks that remain constantly wet are prone to crown rot. Mulch piled high against the trunks/stems of young trees and shrubs may also create habitats for rodents that chew the bark. This can girdle and kill the plant.

  • Mulch out to a tree's drip line
    or beyond, at least an 8' diameter around the tree. Remember that in a forest environment, a tree's entire root system (which extends well beyond the drip line) would be mulched.
  • Create self mulching natural areas under trees
    where leaves can stay where they fall. Fallen leaves are a site resource, not yard waste.
  • Avoid thick blankets of mulch and prevent matting
    Matted mulch prevents water and air from seeping through. Rake old mulch to break up any matted layers and to refresh the appearance.
  • Organic mulches may require weeding and replenishment
    once or twice a year to maintain a total depth of 2" to 3".
  • Do not use cypress mulch
    There are no regulations to manage wild harvesting which depletes our necessary wetlands.
  • Shells, crushed stone, or pebbles can be used as mulch
    but they won't contribute to the soil's nutrient and organic content or water holding capacity. Limestone and shells both raise soil pH. These materials also reflect heat. While some Mediterranean plants, like lavender, may enjoy this, the excess temperature can stress other plants and increase their water needs. These mulches are also difficult to maintain. They collect organic debris that is difficult to clean and keep the intended appearance.

HOW MUCH TO BUY?

Mulch is often sold in bags, by the yard, or by the truckload. So, how much mulch do you need for your yard if you want to achieve the recommended depth of 3"?

By the BAG:
1 bag containing 2 cubic feet covers 8 square feet (2' x 4')
By the BALE:
1 bale of pine straw covers 18 to 20 square feet.
By the YARD:
1 cubic yard covers 108 square feet (9' x 12')
By the TRUCKLOAD:
1 mini pickup holds 1.5 yards and covers 162 square feet (9' x 18')
1 full sized pickup holds 2.5 yards and covers 270 square feet (9' x 30')
When purchasing 2 cubic feet of mulch
you will need the following amounts to achieve desired thickness
YOUR PLANT BEDDEPTH OF MULCH
IN SQUARE FEET2 inches3 inches 4 inches
25 sq. ft.2 bags 3 bags 4 bags
50 sq. ft.4 bags 6 bags 9 bags
100 sq. ft. 9 bags 13 bags17 bags

USING YARD WASTE AS MULCH

Search locally for sources of recycled organic materials. Sometimes you can even acquire mulch for free.

Tips on Obtaining Recycled Products for Mulching:

  • Use mulch that originates in your own landscape
    such as leaves, pine needles, or grass and shrub clippings. Chipping or shredding of fallen leaves prevents matting.
  • Local power companies, municipal solid waste departments, and tree services may supply free or low cost mulch
    and may sometimes deliver bulk quantities. Try to get only mulch from branch trimming. It is generally more disease free than mulch from other sources, such as roots.
  • Team up with other homeowners
    and have bulk quantities delivered to your neighborhood.
  • Place an ad in the local newspaper
    so suppliers come to you if you need lots of mulch for a new landscape.

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