Also, cut back anything that reseeds vigorously. All of us have plants that shoot seeds all over the garden. I love liatrus and phlox, but enough already. So, be tough, be brave. Snip off those seed heads to avoid having beds chock full of these beautiful monsters. I'm a softie, so I leave a few stems if the birds love the seeds.
If you have any perennials that are tender - meaning they don't always survive the winter - don't cut them back hard in the fall. The stems and leaves help protect the crown as does a gentle covering of chopped leaves. Mums and tender ferns benefit from this treatment.
Besides plants that are tender, troubled or seedy, I leave most perennials standing for several reasons. I know beneficial insects and butterflies lay eggs and pupate in the leaves and twigs. Birds and other wildlife eat the seeds from many plants. Plus, I like how the seedpods and stems look in the winter. So snip what you must and leave what you can for wildlife and winter interest.
It's tempting to prune trees and shrubs this time of the year, but it's not the best time to snip and clip. Most trees and shrubs should be pruned when they are dormant. Prune deciduous trees (the ones that lose their leaves), evergreens, fruit trees and late-blooming shrubs from January to mid-March. Shrubs that bloom in spring or early summer - like lilacs and forsythia - should be pruned right after they bloom to avoid clipping off next year's buds.
To finish your list of fall chores, take a walk around your yard. Pull up any tender bulbs like calla lilies and dahlias and store them someplace cool and dry. Drain your garden hoses and rain barrels. Clean and sharpen your tools. And remove the support wires on newly planted trees and shrubs if they're nipping the bark or have been on more than six months to a year.
Now, go inside, brew yourself a cup of hot tea and relax. You've done well. Your garden is ready for winter. Your green thumb is greener than last year. Now is the time to dream of next year's gardens.
Annette Ipsan is the Extension educator for horticulture and the Master Gardener program in Washington County for the University of Maryland Extension. She can be reached weekdays by telephone at 301-791-1604, or by e-mail at firstname.lastname@example.org