There are over a dozen varieties of evergreens that will grow well in the Illinois climate. According to the University of Illinois Master Gardener's program, evergreens are recommended additions for any home or roadside landscape. When choosing an evergreen species, site selection is a number one priority. Typically a species of tree may be chosen that will outgrow its location. Planting an evergreen too close to a home may also deter the plant's growth as well. One thing all evergreens have in common is the need for a well drained soil and exposure to full sunlight.
Select a site suitable for the evergreen plant. Avoid areas that have large amounts of shade and soil that does not drain well. Determine whether the evergreen will stand alone or be used as part of a winter windbreak. Most all evergreens are slow growing and will take many years for the plants to reach a mature height.
Plant the evergreens according to the nursery instructions. In most all cases, the transplant holes must be two times to three times the root ball. The root ball may be in a growing container for small evergreens or enclosed inside a burlap wrap for larger specimens.
Dig the transplant holes with the shovel. Loosen the soil on the inside of the hole.
Remove the evergreen from the container or burlap. Align the evergreen so the soil line from the plant matches the existing topsoil line of the transplant hole.
Back fill the native soil around the root ball. Tamp the soil around the root ball with your hands.
Create a soil ring around the evergreen's main trunk that is from 18 inches to 24 inches in diameter and approximately 3 inches high.
Fill the soil ring several times with water to remove any air from around the root ball. This will also improve the native soil contact with the evergreen's roots.
Keep the evergreen well watered, on a weekly basis, during the first season of growth. In most all cases, unless extreme drought sets into your climate, the evergreen will thrive on local area rainfall after the first growing season.
Mulch around the evergreen. Keep approximately 4 inches from the trunk and extend the mulch to the exterior drip line of the outer most branches. Keep the mulch between 2 inches to 4 inches deep under the plant to improve moisture retention and retard weed growth.
Fertilize the evergreen in early spring or late fall. Apply up to 1/3 lb. of a high nitrogen based fertilizer (20-10-5) per every foot of growth. A 6-foot high evergreen will require 2 lbs. of fertilizer. Dig the fertilizer into the soil around the plant. Do not allow the fertilizer to come into contact with any foliage. Water the plant well to dissolve the fertilizer down to the root system. Larger evergreens will not necessarily require fertilizer.
Prune the evergreen to your desired shape before growth starts in the early spring using the pruning shears. A second pruning may be performed during the mid-summer dormant period of the plant. Exercise caution when removing the foliage. Removing too much material may cause a hole in the shape that will take years to re-grow.
Keep the plant in good health as a prevention against pests and disease. Consult your local Illinois county agricultural extension service for any product bulletins they will have concerning specific pest and disease protection for evergreens in your climate of Illinois.