Winter can be a tough time for all of us, even some of our outdoor plants and shrubs. Evergreens and roses will benefit from some protection over the winter. Freeze and thaw cycles and cold, drying winter winds can cause problems for roses and trees. The freeze-thaw cycles cause plant cells to expand and even burst, and the wind can suck every ounce of moisture out of needles and branches. It’s often a combination of the two that causes winterkill.
Here are some ways to prevent winterkill on your roses and evergreens.
Protecting Roses from Winterkill
If your yard often gets hit with 10° or lower, it’s a good idea to protect your roses. There are hardy roses for this climate that will be fine. But, if you have hybrid teas, floribunda, or Grandiflora roses, they won’t take kindly to 10°.
The biggest problem your roses will face is large temperature fluctuations and drying winds. The best way to combat these challenges is to insulate your roses really well.
Having a rose collar, shrub cover, or burlap, makes it easier to keep the insulation contained.
Once all the leaves have fallen off, bundle your rose canes up and tie them loosely together so that it’s a little easier to cover them. You can use a rose collar or a shrub cover filled with a dry material like straw to insulate your roses.
Before you put the shrub cover on, pile some soil up around the bottom of your plant to protect the bud union. Then, once the ground starts to freeze, pack a thick layer of mulch around your rose, at least a foot or two deep. Having a rose collar, shrub cover, or burlap, makes it easier to keep the insulation contained. For insulating material, you can use light mulch, straw, or dry fallen leaves. Basically, any material that is not going to soak up or retain moisture will work. Too much moisture could cause rot. Once you’ve given it a thick insulating layer, cover it with a shrub cover, or wrap it with burlap.
Don’t rush to uncover your roses in spring. It’s best to wait until the danger of freezing has passed.
Protecting Evergreens from Winterkill
Many evergreens are more than hardy enough to withstand an Iowa winter. But, when trees are young, or they’re less-hardy varieties, they will benefit from some winter protection. Freeze-thaw cycles are still a concern for evergreens, but mostly for the roots in the ground. The easiest way to prevent freeze-thaw damage is to give the root zone of your evergreens a thick blanket of mulch before winter hits.
Any evergreen, especially ones with exposure to high winds, can experience winterkill on branches and needles. You can spray evergreens with an anti-desiccant spray that will help them retain moisture. Giving your evergreens a long soaking watering in the fall will also help them be more resilient to the wind. For younger evergreens, it is a good idea to wrap them in burlap. Piling snow around them in the winter will insulate even more and give them a nice slow soak in the spring as the snow melts. Burlap also protects young evergreens from hungry deer.
If you have evergreens near the road, they might struggle from the salt spray from winter traffic. If they’re still small enough, wrapping them with burlap will help prevent some salt damage. If they’re too big to cover, you may want to consider replacing them with more salt-tolerant species of trees in the future.
Heavy and wet snow can also cause damage to evergreens. If your trees are still small enough and drooping under heavy snow, you can try to brush the snow off of the branches. But, in the case of an ice storm, do not touch the trees. Ice is much more difficult to remove. You may cause branches to break, or worse, get hit by large falling ice chunks and hurting yourself.
If you need supplies to protect your trees and shrubs this winter, burlap, shrub tents, mulch, or anti-desiccant spray, swing by the garden center on your way home. We’ve got the tools you need to keep your landscape insulated and safe through another infamous Des Moines winter.