As they create their own private gardens and woodlands, gardeners and landscapers follow her example by mulching their new plantings — shrubs, trees, vegetables, ground cover, and annual and perennial flowers — with the same organic materials that she uses: materials produced during plants’ natural life cycles.
In order to thrive, new plantings need every advantage for a healthy start. Sadly, new home developments usually undergo heavy backfilling and grading that alter the naturally occurring proportions of air, moisture, and organic matter in the original soil. Fortunately, over successive years the life cycle of the healthy new plantings slowly recreates ideal soil conditions as it dies and decays. Mulching can accelerate the process.
Organic and inorganic mulching help retain optimal growing conditions in soil by:
· Smothering weeds, so that desirable plants have less competition for water and nutrients.
· Slowing evaporation, extending the time moisture is available to thirsty plants.
· Keeping the soil temperature even by preventing harmful fluctuation during hot and cold extremes.
· Protecting trees and shrubs from injuries inflicted by weed cutters and lawn mowers.
The most common types of organic mulch are:
· Grass clippings
· Pine needles
· Pine, cedar, and other hardwood tree bark
· Wood chips
· Shredded leaves
· Cocoa bean shells
· Pecan shells
· Ground corn cobs
· Household compost
· Mushroom compost
Inorganic mulches, materials that were never part of a living plant or tree, also have a place in landscape projects. Popular inorganic mulches include:
· Lava rock
· Crushed stone
· Plastic sheeting
· Shredded tires
· Woven landscape fabric
Each type of mulch offers specific advantages and disadvantages. It pays to understand as much as you can to prevent wasting your time, energy, and money.
Organic mulch contains living organisms that interact with a plant’s roots to give it the best possible boost toward a long and healthy life. As it decomposes, organic mulch continues to add nutrients to the soil, creating rich topsoil and preventing soil depletion. (Depletion is one reason why farmers who plant fields devoted to a single crop must let their fields lie fallow over a planting season — there isn’t anything left in the soil to produce healthy crops.) Because it can be worked into the surface soil, organic mulch limits soil crusting and compaction, which results in rainwater runoff and erosion and prevents nutrients from reaching plants’ roots. Organic mulch also encourages denser root growth because new roots can grow into the mulch itself.
A few cautions about organic mulches:
· Grass clippings must be relatively weed-free and dried out to prevent matting.
· Clippings from herbicide-treated lawns should not be used.
· Cypress bark mulching is discouraged by many who fear its threat to southern cypress wetlands in states like Florida and Louisiana.
· Organic mulches provide food for birds, insects, and occasionally vermin.
· They naturally decompose, necessitating replenishment every year or two.
· Large pieces of bark will float away during heavy rain; shredded is preferable, especially on slopes.
· Compost decomposes quite rapidly.
On the other hand, inorganic mulches have the advantage of not decomposing, necessitating frequent replacement; and not attracting insects and vermin. Pebbles can be worked into the soil to lessen the risk of compaction. And inorganic mulches can be used effectively to prevent weed growth and mud in otherwise unplantable soil under decks, steps, and storage areas. Many inorganic mulches are not as effective in regulating soil temperature, however, because they tend to absorb the sun’s rays.
Organic and inorganic mulch can be purchased at garden centers and hardware stores, by the bag or in bulk. Some kinds, such as shredded tree limbs, are available at no cost from electric utilities and municipalities. Mulch sales are also popular fund-raisers for students and young people’s organizations.
Through thoughtful mulching — using organic materials whenever possible — gardeners can become an indelible part of nature’s reproductive life cycle. After all, today’s heirloom seeds are the hand-me-downs of tender, lovingly cared-for shoots from another century, maybe even another culture.
Mulch is about more than cosmetics; it contributes to the natural life cycle of trees, shrubs, vegetables, ground cover and flowers, and fosters the healthy growth of desirable additions to the humblest garden plot and most extensive landscape design.