You’ve enjoyed beautiful, early spring blooms on shrubs like forsythia and lilacs. While they looked like a good “hair cut” would have made them look even better, you resisted the temptation. Now that the flowers have faded, you can go ahead with your pruning plans. That way, the shrubs will look nice as foliage plants for the rest of the season.
Most shrubs flower on last year’s wood. Others flower on this year’s wood. Distinguishing flower buds from leaf buds can be a challenge for the untrained eye. If you prune before the shrub flowers, there is a better than 50/50 chance that you will remove branches with flowers, rather than leaves. That’s why we advise you to not prune until after your shrubs flower.
Forsythia, lilacs, rhododendrons and azaleas are examples of shrubs that bloom on last year’s (old) wood. Last fall, both flower and leaf buds formed and overwintered, waiting for spring’s arrival. This year, spring arrived early and many shrubs took advantage of the nice weather to flower early. So, they are now ready for grooming.
Hydrangea and butterfly bushes are popular examples of shrubs that flower on new wood. As the new growth appears, so will new leaves and flowers. As a result, these plants bloom in late spring or early summer. Flowerless canes that are darker in color and older looking than those in flower can be removed while the plant is in flower. This is last year’s wood and will not flower again.
After the leaves have fallen from shrubs that flower on new wood, they should be pruned heavily. Last year’s canes can be removed almost to ground level. Then new canes will grow and flower.
Many of the same pruning practices apply to shrubs as to trees. Branches or canes should be removed at a fork or right at the base. While it may be more labor intensive, each branch should be pruned individually, not sheared. Shearing leaves unsightly stubs that are not healthy for the shrub. Often, power hedge shears also chew up the leaves, making them look as though they were attacked by some unknown leaf eating insect.
The nice part about pruning shrubs is that you seldom have to climb; it is much safer to prune your own shrubs than it is your trees. The same rule applies, though. If you have to climb, even a ladder, call the pros. Ever see the results of someone falling from a ladder into a shrub? There are a lot of cuts, scrapes and bruises.
Happy gardening. Let’s all make the most of this unusual season.