Spring flowering trees and shrubs are nearing the end of their bloom cycles. Forsythia, one of the earliest bloomers, has completed its cycle and most of the yellow flowers have fallen. Many rhododendrons and azaleas are done, or soon will be. Lilacs are nearing the end of their blooming period, except for a few late blooming varieties.
I recommend removing any limp flowers that remain so the shrubs can direct their energy to foliage growth and next year’s blooms, rather than wasting that energy producing seeds.
Since last fall, I’ve been advising you not to prune spring flowering shrubs and trees until after they’ve bloomed. It’s OK to prune now, as soon as the flowers fall. This will give the plants plenty of time to begin the process of setting next spring’s flower buds.
All the rules for pruning trees and shrubs apply now, just as they did last fall. Don’t top. Prune back to a junction rather than leaving stubs. Leave the swollen branch collar, which contain the chemicals that help pruning cuts heal. Don’t paint cuts. Don’t climb ladders. Call our arborists to prune your trees.
Now is a good time to fertilize your spring blooming shrubs and trees to replenish the soil nutrients. Be sure you buy the right fertilizer for the plant. Rhododendrons and azaleas, for example, are ericaceous (erəˈkāSHəs), which means they like acid soil. Since most of our soil is neutral, select a fertilizer blend formulated specifically for ericaceous plants.
Hydrangeas bloom later in the season but you can start having some fun with them now by controlling whether they bloom pink or blue. It depends on the soil pH. Hydrangeas bloom blue in acid soil and pink in alkaline soil. You can actually control the color by controlling the pH. If you prefer pink flowers, work lime into the soil around a hydrangea. For blue flowers, work aluminum sulfate into the soil. You can purchase both at garden centers and home stores.
Plant growth is an annual cycle. You’ve enjoyed the spring color your shrubs and trees presented. Now it’s time to provide the care they need to prepare for next spring’s show. If you’d rather enjoy the show but leave the work to someone else, call us.