How to prepare your flowers for winter
Does fall maintenance for perennials confuse you? How do you know what to cut back and what to leave alone? If you are not sure, this information will help alleviate your worry about putting your perennials to bed for the winter months.
Early fall is too early to start cutting away at your perennials. Cutting back plants too early may result in a sudden soft grow at a time of year that is risky for the plant. Wait until mid to late fall to be sure your plants have reached their natural dormant state.
Once fall has truly arrived with cold frosts and falling leaves, you can really start working on your perennials. Many perennials have very little winter interest and cutting them back in the fall cleans out your beds and makes the ones you leave look even better. Many perennials have very little winter interest and go dormant after a few good, hard frosts, so it’s fairly easy to tell what can be cut off.
Seed-heads of some perennials (Coneflowers, Black-eye Susans, Asters, Shasta Daisies, Astilbe and Autumn Sedum) provide food for finches and other birds, and they look great against a blanket of snow.
These perennials (and also some of the evergreen perennials: Gaillardia, Salvia, Scabiosa, Digitalis, Hardy Ferns) also naturally carry over a low clump of evergreen leaves near the ground, known as a rosette. These lower leaves need to be left alone in the fall. By spring they often look a little worse for wear, but a quick trim (only the brown or dead parts) will tidy them up again.
Evergreen perennials, such as Ajuga, Dianthus, Candytuft, Coral Bells, Liriope and Phlox (mountain pink) should be left to winter over. Just clip off any brown or shredded leaves, check for plant health and leave them alone.
Evergreen perennials can be trimmed back to half their height after they have finished blooming to encourage a dense and bushy habit.
Woody perennials, such as Artemisia, Butterfly Bush, Lavender and Russian Sage are better left alone until well into mid-spring. Watch for the new growth to appear. At that time, you can remove dead stalks and leaves or the entire plant can be cut back to six inches from the ground. They should never be cut right back to the ground as this could cause them to die
Fall-blooming ornamental grasses can be left alone to provide winter interest in the landscape. However we have gotten in the habit of shearing them down before winter.
If left up, they can end up all over the place as a result of the harsh winter winds. If you leave them up, be sure to cut them back or divide them in the early spring.
Moving or dividing perennials in the fall is a great way to reduce your work next spring. The cool, moist weather is an ideal time for perennial roots to become well established, even in cold-winter regions.
Most perennials can be moved or divided after they have reached their dormant state. Remember to always cut back the foliage by at least half to prevent wilting. This helps keep the leaf mass in proportion to the reduced number of roots.
The last recommendation is to make sure you protect your tender perennials with some kind of mulch. The idea of mulch is to add a layer of insulation on top of the soil, preventing sudden changes in soil temperature (from either deep freezing or thawing) that can wreak havoc to their root systems.
Sometimes a full re-mulching is not cost-effective, but adding a little mulch around your perennials will provide much needed protection.