Don’t be too eager to dig into wet soil

The first warm days of spring make it pleasant to work in the garden.

It is best to wait to work your garden’s soil until it dries, even though the early warm days may tempt you to get started in the garden. The structure of the soil can be damaged if you dig while the soil is too wet to work.

Avoid walking in wet garden beds so you don’t damage the soil. You may find that sunny sections of your garden that are well drained dry out much sooner than shady areas. Add compost or other organic matter to enrich the soil as needed when conditions are right.

You may see winter burn on broad-leaved evergreens such as boxwood, rhododendron, holly and needled evergreens such as yew and arborvitae. I have seen a lot of boxwoods showing discolored foliage in gardens this spring.

Winter burn is a cultural condition that affects plants that do not lose their leaves over the winter. Leaves turn yellow and then brown in response to specific weather conditions. Leaves do not actually burn but rather dry up. Salt spray from vehicle traffic can also damage foliage.

Symptoms of winter burn typically appear first in late winter and accelerate in early spring. Various conditions combine to cause leaves to dry out. Mild winter temperatures and warm winter sun both prompt leaves to process water, which cannot be replaced if the ground is either frozen or very dry. Winter winds also contribute to the problem. Winter burn on evergreens is common after extremely cold or very mild winters, and in both cases, it is exacerbated by lack of snow or rain in combination with strong winds and abundant sun.

Wait until new growth appears before pruning out damaged areas if you are not sure whether the sections are completely dead. I have seen boxwood with an overall brownish cast in very early spring that completely greened up later in the season. It is a good idea to plant broad-leaved evergreens where they will have some protection from winter sun and wind.

Check your garden beds to be sure recently planted plants have not heaved out of the ground due to the freeze-thaw-freeze cycles typical in early spring. This tends to happen with perennials and ground covers that were grown in small containers and planted last fall without being mulched. Gently press the crowns of perennials back into the ground but avoid compacting the soil by stomping heavily around plants. Applying a layer of mulch will help prevent additional frost heaving. I have also seen some damage from snowplows uprooting plants at the edge of beds.

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