Trees and shrubs, including balled and burlapped evergreens, can still be planted this month. Plant on a cloudy day, early in the morning, to prevent heat and transplant shock. Water thoroughly and gently at planting time and continue for the first year with 1 inch of water a week, spread throughout the root zone. Mulch root zones to conserve moisture.
Prune spring-flowering shrubs and ornamental trees immediately after they bloom. These include forsythia, viburnum, lilac, small magnolias, rhododendrons, and azaleas. Prune to the ground old canes of forsythia and lilac. Alternative time to do renovation pruning is in late winter when plants are dormant. Deadhead (or lightly prune) spent lilac blossoms to increase flower production. Avoid fertilizer with excessive nitrogen; it can encourage foliage at the expense of flower production.
Lilac blossoms will last longer indoors if they are cut in the morning on a long woody stem when the flower is only half open. Cut a second time indoors before putting in a vase and make a vertical slit up the woody tissue.
Gently pull off dried flowers of azaleas and rhododendrons. New sticky shoots are located at the base of these flower trusses. Take care not to break these shoots when removing flowers. To increase flower production for the following year, pinch off one-half of this new green growth when it is at least one inch in length.