There is never enough time to do all of the gardening chores needed to ensure a truly healthy and productive garden. So, we must pick and choose. There are certain fall tasks that should take priority, and you should focus on those first.
Plant Clean Up. Key to promoting your garden’s health is removal of plant debris that shows signs of fungus or insect damage, to prevent infecting the soil and other plants. Be sure to send this material to the trash, rather than recycling. You should disinfect your pruner blades with bleach after contact with diseased plant material to prevent carry over to other plants. If not cleaned up, problem pests will otherwise overwinter in dead material and infect plants the following spring. Non-evergreen perennial foliage should be cut back to within 6” of the ground once it deteriorates. Beware that certain plants are cold sensitive and should not have their foliage cut back until the end of winter.
Leaf Removal. Be sure to rake leaves from lawns and gardens. A thick leaf layer can smother and kill grass and create a habitat for disease or insects. The leaf mat will absorb moisture and turn into a dense, soggy mass lying against the stems of plants. This constantly wet environment can soften bark and break down stems, making them vulnerable to pests, disease, and frost breaks. It is recommended to chop leaves on the lawn with a mulching mower and leave them to add trace elements to the soil as they decompose. It is also good to reapply chopped leaves to the garden bed as mulch. They should be shredded finely, however, which may mean going through the vacuum or shredder two times. Of course, chopped leaves, combined with green plant trimmings, are the basic ingredients of compost.
Transplanting & Dividing. Some plants can be divided in fall if needed (rampant spreading, dying center) provided the plant bloomed in spring or early summer. For hardy plants, division and transplanting may be useful at this time while the plant is fully visible and a need for reorganization is fresh in mind. The cooler fall temperatures are gentler on delicate transplants.