Benefits of mulch (some types provide more of the following than others)
- They preserve moisture and keep soils evenly moist.
- They help keep ground temperatures consistent during extreme highs and lows.
- They dampen the growth of weeds.
- They keep insects out of the garden.
- They beautify the landscape.
- They condition the soil by adding nutrient rich humus to the soil upon decomposition.
- They work well with spreading plants such as perennials and groundcovers.
- They are derived from renewable resources.
The organic breakdown of the mulch and it's entering into the soil is it's most valuable benefit. Weed barrier does not block weeds but rather, it prevents nutrient rich decomposing mulch from entering the soil and promotes shallow root growth!
Types of Mulch and their Benefits
Hardwood Bark Mulch
Hardwood bark mulch is a blend of hardwood pulp wood and hardwood bark. In the earlier years it was all bark and then as recently as ten years ago they began blending it with a 20% mixture of pulp wood. Hardwood bark offers all of the benefits listed above and is the best at suppressing weed growth. It is prized for its rich natural color. It is the best priced product on the market and certainly has the most benefits.
Pine Bark or Softwood Bark
Cedar & Cypress Mulch
The primary benefit of cedar mulch is its aroma. Being light and consisting of primarily pulp wood and very fibrous bark, it tends to dry out very quickly, causing it to turn white and unappealing. Its benefits are moderate compared to the Hardwood bark which is priced at about half of that of cedar.
Because cypress is naturally tolerant of moisture, it has been prized for its absorbtion ability and by hence, makes for an ideal mulch in dry climates. But do not be fooled. I have seen pulpwood passed off as bark and ground-up lumber and pallets dyed with color stains and passed off as exotic brazilian rainforest products in order to attract high-end buyers who oftentimes have a fancy for the exotic. Cypress mulch, if in fact it is true cypress, has no more landscape value to it than hardwood bark but it is twice to three times as expensive.
How thick should we go with mulch?
On a fresh bed of dirt we recommend 4-5 (un-packed) inches of Hardwood bark. We recommend up to six inches of cedar mulch. The optimum use for colored mulch is to use it in conjunction with hardwood bark. Use 2 inches of colored mulch placed on top of 3 inches of bark mulch. This method provides you with all the benefits of a less expensive mulch with the added benefit of the visual appeal and color selection of the dyed mulches.
When it comes to mulch, bark rules. It's cheaper, more widely available, has the most benefits and can be used as a base for other mulches.
Remember also to use less mulch around ground cover type spreading perennials and never, never, never use weed barrier or fabric.