Be on the lookout for damaged branches

You may be seeing trees and shrubs that have been damaged by rabbit and vole feeding over winter. Stems and branches that have had all the bark around them eaten will most likely die above the damaged section, as food and water will no longer be able to move between the roots and foliage of the plant.

If the damage goes partially around the stem, then it may heal and continue growing. The more bark that has been eaten, the less likely that the stem will live above the damaged zone.

If you are unsure about whether or not to prune it back, then give the plant time to leaf out and see how it does going into early summer. Cutting the plant back now, though, will likely give better results for new growth coming from the base of the plant.

Most trees will need to be replaced if the bark is eaten all the way around the trunk.

• After a long Chicago winter, it is easy to let spring fever take over when ordering plants from catalogs and buying plants from garden centers. Take the time to select plants that are suited to your garden's growing conditions, such as the amount of sun, and fulfill your design criteria to ensure a successful garden. Putting the right plant in the right location will result in a better-looking garden that requires less maintenance.

• Improve the health of your lawn by core aerating. Leave the plugs on the lawn, as they will break down in a short period of time. Do this before applying any pre-emergent herbicides, which form a barrier at the soil surface to prevent weeds from germinating.

Pre-emergent herbicides will also prevent grass seed from germinating, so coordinate any seeding with use of a pre-emergent herbicide.

• Power rake your lawn if you have an excessive amount of thatch (approaching an inch in depth) to help avoid turf problems. It's OK to skip this if thatch is not a problem in your lawn.

Thatch is an intermingled organic layer of dead and living shoots, stems and roots that develops between the green foliage and the soil surface. It builds up when the turf produces organic debris faster than it can be broken down.

Leaf clippings generally do not contribute to thatch buildup, unless you already have a thatch problem, because soil microbes can easily break them down.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.