Ask the Master Gardener: Prepare your garden for the coming winter

Shredded leaves work as a good mulch in the fall. Photo courtesy Metro Newspaper Service

Dear Master Gardener: I am new to gardening; how do I prepare my gardens and yard for winter?

Answer: Here are some suggestions for winter preparation:

  • Pull up dying plants that have had insect or disease problems, you don’t want pests or diseases wintering in your garden. Clean up all plant debris to help minimize fungus. Burn or bag any diseased plants — don't toss them onto your compost pile.

  • Cut back your perennials to about 4 to 6 inches tall after the first killing frost. If you have coneflowers, black-eyed Susan, or sedum you may want to leave some or all of them up to provide seeds for birds. I don’t cut back my ornamental grasses until early spring because they tend to winter better if I leave them up, and I like the winter interest they provide.

  • Some perennials, such as hostas and Solomon’s seal, don’t handle frost well and can get quite slimy and mushy. A neat clump of short hosta leaf stalks will mark where the plant is and prevent you from facing a messy task in the spring.

Related: Master Gardener: Protect your home from the wrath of woodpeckers Woodpeckers can cause thousands of dollars in damages to homes, but there are ways to scare them off.

  • Perennials that are evergreen or semi-evergreen should not be cut back. They include: Bergenia, Heuchera, Hellebore, Dianthus, Tiarella, and Creeping Phlox -- just tidy them up in the spring.

  • If Mother Nature hasn’t provided an inch of rain per week, keep watering trees and shrubs until the ground freezes.

  • Leave pretty plants standing -- they are beautiful in the winter sun, and they also provide vital winter food and sanctuary for birds to nest.

  • Hardy shrub roses need little or no winter protection.

  • Spread several inches of compost or composted manure over your garden to enrich your soil with nutrients.

  • Mulch your garden beds -- shredded leaves are free and improve the composition of your soil. Shred fallen leaves with your mower. As a general rule, the finer the leaves are chopped up the better, as they will break down quicker.

Related: Ask the Master Gardener: Add a splash of fall color to your yard with shrubberies The Brainerd area supports numerous colorful shrubs that show off the splendor of autumn.

  • We’ve had a light frost so go ahead and dig up, cure, and store tender bulbs (calla lilies, cannas, dahlias).

  • Fall-seeded lawns (and newly laid sod) benefit from regular, thorough watering.

  • Garden tools will last longer and work better if you keep them clean and well-maintained. Shovels, rakes, trowels, and other tools can be washed with water and then dried well. Another method of cleaning shovels and pitchforks is to slide them up and down in a bucket of sand (you can also add some motor oil to the sand). To prevent rust or minimize it, lightly oil your tools made of steel. Before putting them away for the winter you may want to sharpen your trowels, shovels, and hoes with a hand file and your pruning shears and garden knives with a honing stone. When spring arrives, you will be glad your tools are in tip top shape!

Dear Master Gardener: We have fungi growing in our mulch. Should we do something about it and will it hurt our plants?


Answer: Wood and bark mulch decompose over time. The primary organisms involved with their decomposition are bacteria and fungi. Slime molds, stinkhorns, and bird’s nest fungi are the fungi most commonly found in mulch. Because these fungi only live on decaying plant matter, they do not harm living plants.

Dear Master Gardener: I think I may have some spider bites on my arm and was wondering if I should spray my whole house to prevent spiders from coming in?

Answer: It is common to think that a skin irritation could be a spider bite, but spiders very rarely bite people. Even the feared black widow and brown recluse spiders are not aggressive and shy away from people, but don’t worry because neither one is native to Minnesota. Spiders can enter your home any time during the year; however, you will be more likely to find them in late summer and fall when they are looking for winter hibernation sites. You are also more likely to find them in homes located by rivers, lakes or fields. If possible, try to tolerate spiders because they are very beneficial to the environment and consume lots of insects, including pest insects. If small numbers are found, the easiest control is to capture and remove them. If tolerating them in and around your home is not an option, then try to use a nonchemical method first. Regular housecleaning is very important in controlling spiders in your home. Other ways to reduce the number of spiders in your home are:

  • Remove papers, boxes, bags, and other clutter to minimize favorable sites for spiders.

  • Remove webbing with a broom or vacuum, and destroy any egg sacs and spiders that are found. Look especially around windows, in corners and other relatively quiet places.

  • Eliminate insects that serve as a food supply, especially when large numbers exist. Check in and under webs to see what insects have been captured.

You can supplement your sanitation efforts with an insecticide treatment, applying it behind baseboards, in cracks and crevices, and other places where spiders may hide. According to the entomology department at the University of Minnesota, general treatments on surfaces and fogs are not effective. Most insecticides labeled for ants and cockroaches are also labeled for spiders.

You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A Master Gardener will return your call. Or, emailing me at and I will answer you in the column if space allows.
University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.
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