Use Mulch Appropriate to the Plants

An example most of us can readily relate to in understanding mulching by natural means is that of the leaf and plant litter on the forest floor. It is easy to witness the buildup of organic mulch with even one pine tree. Needles, bark and twigs are shed throughout the year, layering the soil. Leaves from surrounding trees blow in too. The bottom most mulch material slowly decomposes as new mulch is slowly added. Walking is softer, almost springy in some cases. Earthworms, an indicator of healthy soil, will be present in soil mulched over for a number of years and are closer to the surface. If you ever have the opportunity to dig in a wooded area, and then in an area adjacent to it not wooded or mulched, you will certainly experience the difference in soil textures.

The shortgrass prairie’s manifestation of natural mulching isn’t as apparent. Trees and forests are in short supply. But our abundant wide-open plains nurtures short grasses and forbs that follow a similar cycle of the seasons. Autumn’s spent leaves provide groundcover for soil, seeds and wildlife throughout the cold winter months, giving way in springtime to new growth. Eventually, yesteryear’s prairie decays, building and replenishing the soil, though at a much slower rate. When rangeland is spared over-grazing, our prairie’s natural mulch is more apparent, just not as spongy and moist as the forest floor.

Plants that thrive in the shortgrass prairie community are tolerant of their climate and conditions. The constant struggle between fire, wind and hail, the cloudless blazing sky, blizzard, cloudburst and drought, hardened and toughened our steadfast prairie stalwarts. The thin layers of vegetative debris or rock, stone and gravel cover provide ample mulch for shortgrass prairie survivors. Plants and animals, soil and climate conditions coexist in an ecology developed over the ages. To garden more naturally within the scope of our environment, and with less maintenance, look to nature and mimic her conditions and solutions.

Different ecosystems or biomes accumulate different mulches. Botanical gardens across the United States, and no doubt the world, use mulch found in the plant’s natural habitat. In creating these display gardens, they seek to use mulch that denote a sense of place, not looking “out of place”. Some botanic gardens, such as the Denver Botanic Gardens, do not even use organic mulches for plants native to the western United States: “ ‘We don’t use any organic mulches unless you count top dressing, which is applying several inches of compost to perennial beds and shade gardens,’ ” according to Rob Proctor, DBG’s artistic director. “Even the use of compost as a top dressing and soil amendment is limited to shade plants that are not native to the region. ‘Putting an organic mulch, such as bark, on other types of beds,’ Proctor explains, ‘is completely unnatural for this region.’ Taking further cues from nature, Proctor adds, ‘we do use inorganic mulches, specifically pea gravel, in areas where we have rock garden plants or native western plants that evolved in stony soil.’ ” (“Smart Mulching”, by Rita Pelczar, The American Gardener Magazine, January/February, 2003.)

All bare ground in your landscape should be mulched. Mulches can be organic or inorganic. Different mulches are used for different purposes; use the most appropriate mulch for your plant type or purpose. Our home landscapes have many different micro-niches in which we use plants best suited for them. Some mulch is more useful for covering beds, borders or vegetable gardens, while other types of mulch are more suited for paths and walkways.

For medium and high water use areas (where plants from ecosystems and regions other than our own) benefit more from organic mulches. By far, compost is the best mulch to use, but there are others you may select. More than one type material is found naturally covering the ground in a forested area. Avoid scrupulous bed and border cleanups. Mulch cover and plant debris from the plants themselves provides habitat in a healthy ecology. Leave mulch material to protect the soil, plant and beneficial animal life, both micro and macro organisms.

Overview of this Basic Principle of Gardening – Using Mulch

Organic mulches are straw, grass clippings and healthy chopped plant debris, shredded bark, wood and bark chips, pine needles, compost, humus, cottonseed hulls, cocoa bean hulls, pecan shells, peanut hulls, chopped and crushed corncobs, mushroom compost, shredded newspapers or other papers (depending on ink used), leaf mold, chopped leaves, and living plants. If you're an impatient composter, "almost compost" makes excellent mulch.

Some inorganic mulches are crushed gravel and granite, small stone, lava or granite rock, decorative and colored stones, sand, plastic, or crushed brick and crushed, tumbled glass.

In this principle on using mulch, I describe the benefits of mulch, the different types of mulch to use, both organic and inorganic, mulch tips and uses, mulch insights and cautions, mulch and extending cold hardiness, how mulch helps to conserve water and how mulch helps moderate soil conditions and our extremes of climate. As you will learn, there is much, much more to mulch than just wood chips or volcanic rock. If you haven’t used mulch before, I hope you start using mulch and reap all these benefits.

Please read through this entire section on mulch, especially the cautions and insights section under Much More about Mulch and use whatever mulch is most appropriate for your plants and pocketbook.

Angie Hanna, July, 2006