Spring is popping up all over, in the form of early bulbs

I just returned home from skiing and found all the snow gone and some bulb foliage popping up. It is starting to feel like spring in the Chicago area.

During periods of warm weather, early bulbs might begin sprouting, especially those planted with a southern exposure, close to a house or garage. The Botanic Garden has had snowdrops in flower in late February in similar locations.

Foliage is the first greenery to show, with flower buds appearing much later in the bulb’s growth. Subsequent cold weather might damage the edges of the foliage, but unless the flower bud has appeared, it will not affect the future flowering or health of the bulb. A few small early bulbs can tolerate a bit of frost. These include winter aconite, snowdrops and glory-of-the-snow.

How to handle winter burn

You may see winter burn on broad-leaved evergreens such as boxwood, rhododendron and holly and needled evergreens such as yew and arborvitae. 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 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 is common after extremely cold and extremely mild winters, and in both cases it is exacerbated by lack of snow or rain in combination with strong winds and abundant sun.

Most often, it is best to wait until new growth appears before pruning out damaged areas. This is especially true 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. In general, it is a good idea to plant broad-leaved evergreens where they will have protection from winter sun and wind.

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