Perennial gardens in cold and extreme winter growing zones require winterizing to decrease the amount of work needed once the spring season rolls around. Don't rush to winterize a garden until the weather conditions and plant growth dictate it is time. Begin preparing the garden once the plants begin to die back and after the first hard frost of the season. Make a garden winterizing plan in late summer to eliminate the last-minute rush.
Stop fertilizing all perennial plants in late summer to prevent excess foliage growth, which weakens the plant prior to the winter season.
Deadhead fall blooming plants by removing spent blooms to lengthen the bloom time until frost kills the plant. Remove plant foliage from plants that are past their lifespan and are yellow or dry in color. Cut the plants stems at several inches above ground level.
Collect seeds from flowering perennials that you want to re-seed in spring. Cut the seed heads from the plant, separate the seeds and dry them thoroughly. Store the seeds in a paper envelope until seeding time in late winter or early spring.
Remove perennial and annual weeds before they go to seed. This prevents new weeds from growing in the spring. Do not throw weeds with seed heads in the compost bin, as the seeds will sprout in the spring.
Divide and move plants that are overgrown or planted in the wrong location. Plants should be divided and replanted at least six weeks before the first hard frost so they have time to acclimate to the new location and begin root growth before winter.
Remove tender bulbs from the ground after the first frost to store for winter. Spread the bulbs out in a cool location to cure them. Toss shriveled and diseased bulbs. Store the bulbs in a cardboard box filled with peat moss placed in a cool, dry location.
Place winter mulch around perennial plants in late fall to insulate the roots during the winter. This will decrease damage to the plant by insulating the ground to prevent winter heaving. Evergreen boughs or clean hay and straw are good choices for winter mulch.