Winterizing Your Perennials
By Ben Polzin, Down To Earth Garden Center
Winterizing your perennials garden doesn’t have to be a big job, especially if you take little steps all year to prepare your plants for whatever nature gives us. The most important task is getting any diseased foliage cut back and removed to prevent any unwanted diseases or insects from overwintering in the plant or soil. Spending a little time in the garden this fall will help your plants reach their potential next year. It’s a great time of year to be out and enjoy the sights, sounds, and smells of fall. Relax and enjoy the task; it’s the one chance you have to do a cleaning job that stays done for six months.
► How do I know what my plants need? While some varieties of perennials may need more protection than others, all of them will benefit from your attention ► When should I cut back my perennials? Most perennials are cut back after we have had a killing frost in the fall. This usually occurs in early October. It is important to clean off all plant debris after the frost to help minimize soil-borne diseases. ► What kind of protection should I provide? Most perennials simply need a good layer of mulch applied late in the fall. The purpose of mulching in this case is to protect the crowns of the plants from the alternate freezing and thawing that occurs very late in fall and in early spring. It is important that the ground be allowed to get cold before mulching, so wait until early to mid-November before covering the plants. Ideally an inch or two of frost in the ground is best. ► Are some mulches better than others for perennials? There are several mulches that work well for winter protection of perennials. Straw, hay, and leaves are the most common. ► How much mulch should I use? A layer 4 to 6 inches deep is best for most perennials. ► Are there any perennials I shouldn’t mulch? Bearded iris should either go without mulch or be mulched extremely late. The iris borer seems to be worse on mulched plants, especially those mulched early. If you have had any disease problems with your peonies, leave them unmulched as well. ► Should I continue to water in the fall, even after a killing frost? Making sure your perennials stay WELL watered until the ground freezes is important to successful wintering. Quite often we go through several dry weeks late in October. If the soil is dry an inch or two below the surface, give the area a thorough soaking. ► Can I divide or move my perennials in fall? Many perennials can be divided or moved in fall. Generally if a perennial blooms in spring or early summer, it can be divided or moved in fall. If it blooms in late summer or fall, it is best divided or moved in spring. There are a few exceptions, of course. Irises and day lilies prefer to be divided in August, and a few plants with taproots don’t ever want to be disturbed. ► When can I remove the mulch in the spring? Wait until all the frost is out of the ground before removing the mulch. If it gets very warm early, you may want to pull back part of the mulch, but leave at least 2 to 3 inches.Some gardeners leave mulches in the beds, just pulling them back away from the crown of the plants. This adds organic matter and helps suppress weeds. Mulches that have been removed can be composted.