Growing plants from seed allows you more choice

It is time to start annuals from seed that are slow to start and develop, such as pansies, violas, petunias, snapdragons and lobelia. While garden centers offer many favorites, there are many more choices when you grow your own.

Use grow lights to ensure success without a greenhouse environment. A florescent bulb hung on a chain works best as you can adjust the level to keep the light at an optimum 8 to 12 inches above the seedlings. Providing bottom heat for the seedlings will also improve results. Heat mats or cables may be purchased at your local garden center.

Thin seedlings as needed, especially after the first set of leaves form, to prevent overcrowding and keep the best plants. Sow a few extra plants to make sure you produce enough.

• Winter is a good time to prune trees and shrubs. Heavy pruning of overgrown deciduous woody shrubs can be done this month and next to rejuvenate them. Start by removing all dead wood and prune old stems off at ground level, leaving young stems. You may need to cut back the young growth if it is spindly.

If there are not any young stems present, cut the large stems back to 2 to 3 feet from the ground. This will be unsightly, but if the plants are healthy, extensive new growth should start from the old canes in spring and fill in the plant. Shrubs such as lilacs that formed flower buds last summer will not bloom in spring when pruned aggressively in the previous winter.

• Stems from spring-flowering trees and shrubs can be forced to flower at this time of year. Prune those branches that are not essential to the plant's basic shape or save branches from your winter pruning. Branches should be at least 1 foot long, full of fat flower buds and cut on a day when the temperature is above freezing.

Cut the ends at an angle and put into water in a cool room out of direct sunlight. When the buds color up or the foliage begins to unfurl, arrange the branches in a vase and display them in a cool room out of direct sunlight.

Good choices for forcing within the next month include lilac (Syringa), serviceberry (Amelanchier), magnolia (Magnolia), flowering quince (Chaenomeles), forsythia (Forsythia), crabapple or apple (Malus), flowering pear (Pyrus), flowering cherry (Prunus), spring-flowering witch hazel (Hamamelis vernalis) and redbud (Cercis).

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