Mulching the bare soil around plants is a major part of basic water conservation and for the health of the plant and soil. It should be the last step when new planting is done. I’m sure you know that a healthy layer of mulch keeps weeds from growing, helps reduce water loss due to evaporation, keeps the soil cooler, and (depending on the type you install) will break-down in time to add nutrients to the soil, and protect against harsh weather in winter, recycle local materials, are loaded with nutrients, lock together and stay in place well, breathe properly and break down fairly quickly to feed microbes in the soil…WOW!
That’s a lot that just a little layer of mulch can do. But, there are some good and bad choices. I’m going to liberally borrow from The Dirt Doctor, local Organic Gardener Howard Garrett, and his expertise on mulch. Here’s a rundown for you and some tips that might help choose the best mulch for your yard.
- Shredded native mulches are the best choices; they provide all the benefits listed above. As a Round Rock water customer, you can get FREE hardwood mulch at our brush recycling center!
- Pecan shell mulch is a fairly good choice if it is partially composted first. Fresh, new shells don’t behave very well. Like pine bark, they blow and wash around and fresh shells usually have some pecan meat left that may attract fire ants. Boo.
- Partially completed compost is good mulch. When ingredients are still identifiable this compost shouldn’t be used in bed preparation, but it is good to use as a topdressing mulch.
- Shredded hardwood bark is a good mulch. It is not as good as shredded tree trimmings because of much less nitrogen. As opposed to shredded tree trimmings, there is little protein tissue (buds, stems, cambium, leaves, etc.) that is the source of nitrogen and other nutrients.
- Pine straw or pine needles do not have the same natural chemical issues as pine bark. Plus they stay in place and work well as mulch. Only issue is that this mulch can look out of place if no pine trees are growing on the site. This is an excellent mulch for the vegetable garden because it breaks down quickly and effectively helps feed the soil.
- Lava gravel is an excellent mulch if you like the look. It helps grow plants and helps keep them healthy.
- The worst choice – rubber mulch made from ground up tires. It’s full of toxic chemicals, doesn’t break down to feed microbes, and holds heat that will damage microbes and plants. This product should never be used.
- The second worst mulch – colored mulch. These red and black products are all over the place in the marketplace but should not be used. Some of the dyes used in these products are very questionable in toxicity, but there are more serious problems. These “mulches” are made from ground-up wood such as siding, pallets, lumber, etc. These things are all carbon and totally unbalanced due to lack of protein/nitrogen. They not only don’t feed the soil properly, they actually rob nitrogen from microbes and soil health.
- Cocoa mulch, also a bad one. It smells good, but is expensive and very dangerous to dogs. Don’t use.
- Cypress breaks down very slowly. That’s not what we want. The rotting of mulch is an important source of natural fertility. Cypress also tends to fuse together and not breathe properly. The way it is harvested from wetlands and shipped across the country is an environmental problem. Not a good choice.
- Pine bark, also not the worse, but not the best. The large nuggets are better than the medium and fine-textured products since they will at least stay in place a little better. The small pieces blow and wash away to eliminate the benefit and create a maintenance problem. Plus, all pine bark products contain natural chemicals that are not good for soil health or plant growth.
- Volcano type mulching looks horrible and because it is piled high up on the tree trunk, the flare is completely covered and the moisture kept on the trunk is highly detrimental to the tree. Tree flares should always be exposed (of course) and proper mulching should not be piled up on stems and trunks of plants.
- Plastic barriers. Shredded tree trimmings are an excellent mulch choice, but when plastic is used under it, the benefits are eliminated. Mulches should touch the soil so that their breakdown into humus feeds the life in the soil. Also the plastic prevents water from soaking into the ground, which is exactly the opposite of what we want!
Good luck in picking out the best option for your yard! I have used the City’s free much for over 10 years now in my yard with no issues. It looks great! I replace it annually since it does break down and layer it around trees and in beds about 3-4 inches deep.