How one cares for the garden and landscape in the fall determines how well the garden will perform next spring. In the past, the cleanup ritual has focused on removing plants that have been killed by frost or have finished flowering. Pulling tomato vines or marigolds up by the roots has been an accepted practice for years. Recent studies have shown that the rush to rid our yards of last year's plants and get down to bare soil may not be in our best interests.
While removing diseased leaves and stems may help reduce the likelihood of the same problem recurring next year, the removal of all dead plant matter removes sources of food and over-wintering sites for beneficial insects. The destruction of habitat for beneficials is one of the most underrated sources of problems in the garden. Without a supply of garden helpers, early season insects like aphids can quickly get out of hand and force the gardener to the spray bottle.
Fallen and decaying leaves have been nature's way of fertilizing plants since the first green life began on our planet. Many urban gardeners bag and send this precious non-polluting form of plant food away from their gardens. It may take more work to use this free source of nutrition than buying bagged fertilizer, but it is well worth either composting or storing the leaves for later use. Clever gardeners now use leaves as mulch and cover them with a thin layer of bark chips to hold them in place during winter's stormy weather while keeping a neat appearance in the yard.
Pulling spent plants from the ground by the roots disrupts the final act of the cycle of life. Allowing the roots to remain in the soil by clipping the plant at the soil line provides spaces for air and water to penetrate as they decompose. The soil colony of bacteria and microbes remains intact and feeds on the decaying plant material. The soil drains better and crumbles more easily and organic mulches have openings to begin working their way down into the soil.
Tilling under the vegetable garden at the end of the season to get rid of plant material has come under close scrutiny. Many gardening experts now believe that the only time when rototilling is beneficial is when turning sod under to start a new garden area or when it is necessary to incorporate large amounts of organic matter into a needy soil. Beyond that, it can be defeating to gardening efforts by bringing large numbers of dormant weed seeds to the surface to sprout. It also infuses the soil with large amounts of oxygen, which stimulates a feeding frenzy by microbes, effectively starving millions of them and making it difficult to rebuild their population.
Removing old seedpods from perennials may remove potential sources of food for birds and other animals. Many grasses put up attractive and nutritious seed heads in fall. Cutting down these plants removes this source. Roses provide healthful hips if left intact. Many other ornamentals can provide shelter from winter storms if not sheared or pulled.
Perennial flowers that maintain green basal growth through the winter like Shasta daisies and gaillardia, will benefit from removal of the dead stems and leaves while leaving the new leaves to grow. Less hardy perennials like lavender should not be pruned or shaped until spring growth commences in earnest.
This new way of looking at fall cleanup results in less work for the gardener and is more aligned with the natural world. We can't expect a better partnership than that!