Spring is an exciting time for gardeners, marking the beginning of the growing season. As buds emerge and pollinators return, trips to the garden center become a regular weekend activity. While the temptation to start pruning early is strong, it’s important to be cautious with your shears. Many plants flower on old wood, so pruning too soon can remove flower buds before they have a chance to bloom.
To help your hard work pay off, experts advise against pruning certain plants in the spring. Rhododendrons, for example, develop flower buds the previous year, so pruning them in spring can prevent blooms. Forsythia, one of the first plants to emerge, should be pruned after flowering. Specific hydrangea varieties, like bigleaf and oakleaf hydrangeas, bloom on old wood and should only be pruned after flowering or in late summer if shaping is necessary.
Magnolias set their flower buds in late summer and fall, so spring pruning removes the upcoming season’s blooms. Weigela, which blooms on old wood, should be pruned after flowering to avoid impacting its spring display. Native coneflowers and milkweed should also be left alone until later in the growing season to protect emerging shoots and provide food for wildlife.
By following these tips, you can ensure a successful and vibrant garden throughout the spring season.
“Trimming too early can harm new growth and disturb overwintering pollinators,” advises Funk. “Wait until you observe fresh growth at the base before pruning last year’s stems.”
Lilacs bloom on old wood, forming flower buds during the previous summer. “Pruning in spring can remove these buds, significantly reducing or even preventing that year’s blooms,” explains Funk. “The optimal time for pruning is immediately after flowering to promote new growth for the following year.”
Bleeding heart naturally dies back after blooming, and cutting it in spring can weaken the plant. “The foliage stores energy for next year’s growth, so it should be left untouched until it yellows and naturally dies back in summer,” suggests Funk. “If reshaping is necessary, wait until after the foliage fades.”
Columbine is a self-seeding plant that re-blooms better the following season when its foliage remains in spring. “Pruning too early can remove developing flower stalks and diminish its ability to reseed,” Funk cautions. “If tidying up is required, wait until after flowering to remove spent blooms or excess growth.”
Viburnum comprises around 175 species and numerous varieties, with most native to the northern hemisphere, according to Roethling. Viburnum usually blooms in spring, so it’s advisable to postpone pruning until after the blooms fade in early summer. Pruning too soon may result in minimal to no blooms, adds Roethling.
Flowering quince is a deciduous shrub that should not be pruned in spring, as it will remove its showy flowers. “Shrubs should be pruned immediately after the flowers are finished and before the leaves fully emerge,” advises Roethling.
