Using Compost Around Trees and Shrubs
While this statement might be a surprise to you, the soil under all trees and shrubs in the home landscape should be covered by either a mulch or a ground cover; not by turfgrass. Trees and shrubs surrounded by lawn grass are vulnerable to serious problems. They are more likely to be injured by lawn mowers and weed trimmers which move close to their stems to cut the grass there. They also must compete with the hungry grass plants for both food and water. Trees and shrubs stand to benefit from a mulch amended a bit with compost just as much as marigolds and tomatoes do. Again the problem is one of supply and need. It takes a considerable amount of compost to mulch around a large shade tree.
At the same time, those homeowners who do not have flower or vegetable gardens but have lots of trees, can recycle the leaves and trimmings from the trees on their property into compost in enough abundance to amend the mulch under these same trees and shrubs periodically with some passive compost from the leaf pile out by the back fence line. Don’t worry about being precise. Any compost sprinkled under any tree or shrub at any time is going to do good things.
For those trees that already enjoy a mulch of live groundcover plants, we suggest you save your compost for someplace else. Usually groundcovers capture falling leaves in the fall and make their own compost over time; and you never see what is happening.
Use Compost For Special Plants – One way to allocate a limited amount of compost is to identify particularly important trees or shrubs on the property and that is where you will use some compost. Use it for special treatment of those plants that have sentimental, historical or horticultural value or that may need extra tender loving care because of injury or illness. hole.
Tree Surface Roots -- Trees whose roots are exposed on the surface of the soil are at particular risk of injury from mechanical yard care equipment. Also, the protruding roots endanger people walking on the lawn and look unsightly. Sometimes homeowners try to solve the problem by covering the exposed roots with a generous layer of soil. Unfortunately this harms the tree even more and is likely to kill it.
To cover the surface roots of trees safely, it is important to use a very light soil mix and spread it very thinly over the area. To lighten soil, add compost in a ratio of half soil to half compost. Spread this mixture only 2 inches thick over the roots. A thicker covering will literally smother the exposed roots, which have become accustomed to getting lots of oxygen. As rain washes between the roots and the compost and soil become integrated into the surrounding soil, it will be necessary to recover the roots. Do this as often as it takes to establish a good covering of soil over the roots, as often as the compost supply permits, and as long as the covering is never more than 2 inches thick at any time. It is wise to aerate the area under a tree with surface if you happen to have a hand aerating tool.
Compost As Poultice For Tree Injuries -- For centuries, farmers with a special feel for the land, would treat a wound on a tree with a handful of soil, held against the wound with a rag or tape of some kind. Researchers in the past 20 years have confirmed that the microbial content of the soil has disease fighting and disease preventing capabilities. Actually most of the research has been done to confirm that compost is even better than plain soil. It is alive with beneficial microbes that will take over the area of a wound and prevent harmful pathogens from getting a foothold. Studies have concluded that tree paint, for years used to cover saw cuts and wounds on trees, has no beneficial value.
Compost, on the other hand, has remedial value in a case where a tree or large shrub has been damaged and the bark is broken making the tree vulnerable to disease pathogens. If a tree has been wounded by a lawn mower or a weed trimmer, or has suffered damage from wind or storms, a poultice of compost is as good a treatment as you can find to prevent disease in a wound. Dampen the compost slightly and lay it on the wound, taking care to cover the entire injured surface with compost. Then wrap the area with Tree Skin(TM) or some other biodegradable material such as cotton cloth. After a few months, when the tree has calloused over the wound, remove the tape or wrapping if it has not already rotted away.