Here it is: Plants that produce flower buds on last year’s wood should be pruned in late spring or early summer, soon after the spring flowers have fallen. For instance, when your lilacs have finished flowering in April, prune them at that moment or in May. It would be nice to say, prune plants with significant flowers in the summer after flower drop, but there are some exceptions. Can you name some? Conversely, plants that produce flower buds on new wood, or wood that has just been made in the spring should be pruned in winter, or early spring just prior to bud break. I think we have become confused by trying to differentiate between early spring and late winter. Just concentrate your efforts between January and the end of March in the Mid-Atlantic and you’ll be fine. One comment on that. There are plants such as peach trees and some evergreen shrubs that can be damaged by sub-zero weather or severe temperature fluctuations. Try to hold off pruning until the threat of such weather has passed but before spring growth begins. Almost all of our evergreen shrubs are done during this time, so they are easy to remember as a large group. Does that make sense? This does not mean we cannot prune plants that flower on old wood such as lilac, forsythia or azalea in the winter. Just be aware that when you do, you will cut off flowers that were produced during the last calendar year. We sometimes do this when we drastically reduce or rejuvenate plants. This way all new growth begins just after pruning, producing vast amounts of green, leafy material used for food production by the plant. You will only lose flowers for one season by pruning these plants during the dormant season, then you can return to your regular pruning schedule during warmer weather, next year. It’s also good to remember that not all plants can withstand renewing or rejuvenating. For instance, azaleas and yews respond to hard reduction pruning quite well, while junipers are less tolerant. Therefore, when pruning junipers, be gentler, leaving lots of green leafy material for next year’s food production. Rather than go over the timing for each plant individually, here is a brief list of the major plants in our temperature zone that should be pruned during the dormant season, when cold, before growth begins. Prune any others after flowers fall in spring or summer. I recommend the use of high quality bypass pruners, a good sharp pruning saw and of course, the eye of an artist to bring out your plant’s innermost beauty. Think of your plants as your canvas and your pruners, your brush. Have fun and remember, no stubs or flush cuts!
PRUNE BEFORE ANY GROWTH BEGINS IN DORMANT SEASON
- Abelia
- Rose of Sharon
- Barberry
- Butterfly bush
- Callicarpa
- Caryopteris
- Clethra
- Hamamelis (witch-hazel)
- Hydrangea
- Japanese Kerria
- Lagerstroemia
- Ligustrum, this includes privet.
- Smoke tree
- Japanese tree lilac, not to be confused with your common lilac shrub. Be sure to prune the shrub lilac in spring/summer as soon as flowers have fallen.
- Roses (shrub varieties). We will have a more in-depth look at roses and a few other things later.
- Spirea. Here’s some clarification: There are many varieties. Prune Anthony Waterer and Douglasii in winter and bridal wreath, Thunbergii and Van Houtei in spring/summer after flowers have fallen. Some resources tell you to lump them all together and cut after flowering. This will assure flowering after pruning, next year.
- Tamarix
- Viburnum (berry bearing). We will also discuss this genus in greater detail, later.
- Vitex
- Prune your orchards during dormant season
- Prune your evergreen shrubs such as hollies, boxwood, yews, junipers, cedars
- Deciduous ornamental trees and large shade trees should be done during the dormant season.
Should you find any particular plant confusing, let us know.