12 Plants You Should Never Prune in Spring, According to Gardening Experts
Spring is one of the most exciting times of year for gardeners as it signals the start of the growing season. Buds begin to sprout from the ground, pollinators make their return, and trips to the garden center become a regular weekend activity.
While the urge to get outside and fix up your garden on the first warm days of the year is strong, don’t go overboard with your pruning shears. Many plants bloom on old wood, meaning pruning them too early can remove their flower buds before they get the chance to show off.
To ensure all of your hard work pays off, we’re sharing which plants experts say you should never prune in spring.
- Kelly Funk, president and CEO of Jackson & Perkins, a mail-order plant and seed company
- Adrienne Roethling, head gardener for a private estate and former curator of Juniper Level Botanic Gardens at Plant Delights Nursery
Rhododendron
Rhododendrons (Rhododendron spp.) also develop their flower buds the previous year. “Spring pruning will cut off these buds, preventing blooms for the season,” says Kelly Funk, president and CEO of Jackson & Perkins, “If pruning is necessary, do so immediately after flowering to maintain shape without sacrificing flowers.”
Forsythia
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Forsythia (Forsythia ssp.) is one of the first plants to emerge in spring. In mild winters, they may even appear in late February or early March. “Forsythia can be an unruly plant and may require regular pruning,” says Adrienne Roethling, head gardener for a private estate. That said, it’s best to wait to prune this plant until after it’s done flowering.
Hydrangea
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Specific hydrangea varieties, such as bigleaf (Hydrangea macrophylla ) and oakleaf hydrangeas (Hydrangea quercifolia), bloom on old wood. “Cutting them in spring removes the flower buds, leading to little or no blooms that year,” says Funk. “Prune only after flowering or in late summer if shaping is required.” Panicle hydrangeas (Hydrangea paniculata) and smooth hydrangeas (Hydrangea arborescens) bloom on new wood and can be pruned in late winter or early spring.
Magnolia
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Magnolias (Magnolia spp.) set their flower buds for the following season in late summer and fall, meaning spring pruning removes the upcoming season’s blooms. “These trees also don’t heal well from heavy pruning, making unnecessary cuts more harmful than helpful,” says Funk. “If pruning is required, do it right after flowering or in late summer.”
Weigela
Weigela (Weigela florida) blooms on old wood, so wait to prune until after it flowers in mid to late summer or you risk preventing a lush spring display. “While the urge to thin out the center or shape the overall habit in winter is there, the risk of cutting flower buds runs high,” says Roethling.
Coneflower
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Leave native coneflower (Echinacea spp.) alone until later in the growing season. “Old coneflower stems protect emerging shoots and provide food for birds in winter,” says Funk. “Cutting them too early can expose tender new growth to late frosts and remove valuable seed heads. Wait until new shoots are several inches tall before cutting back last year’s growth.”
Milkweed
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Milkweed (Asclepias spp.) is slow to emerge in spring, and its old stems remind gardeners of where it will regrow. “Pruning too early can damage the new shoots and disrupt habitat for overwintering pollinators,” says Funk. “Wait until you see fresh growth at the base before cutting back last year’s stems.”
Lilac
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Lilacs (Syringa spp.) bloom on old wood, meaning they form their flower buds during the previous summer. “Pruning in the spring removes these buds, significantly reducing or even eliminating that year’s blooms,” says Funk. “The best time to prune is right after flowering to encourage new growth for next year.”
Bleeding Heart
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Bleeding heart (Dicentra spectabilis) dies back naturally after blooming, and cutting it in spring can weaken the plant. “The foliage helps store energy for next year’s growth, so it should be left alone until it yellows and naturally dies back in summer,” says Funk. “If shaping is needed, wait until after the foliage fades.”
Columbine
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Columbine (Aquilegia spp.) is a self-seeding plant that re-blooms better next season when its foliage is left intact in spring. “Pruning too early can remove developing flower stalks and reduce its ability to reseed,” says Funk. “If tidying is needed, wait until after flowering to remove spent blooms or excess growth.”
Viburnum
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Viburnum (Viburnum spp.) makes up approximately 175 species and hundreds of varieties with most species native to the northern hemisphere, says Roethling. Viburnum typically flowers in spring, so it’s best to wait to prune until after the blooms fade in early summer. Pruning too early may result in little to no blooms, Roethling adds.
Flowering Quince
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Flowering quince (Chaenomeles specios) is a deciduous shrub that should never be cut back in spring, or you will remove its showy flowers. “Shrubs should be pruned right after the flowers are done and before the leaves fully emerge,” says Roethling.
