“Prune my shrubs and trees in December?” you ask. Depending on which plants you have in your landscape, this can be the perfect month to clip these plants. Follow the following winter pruning tips for more information about the varieties you can prune and why.
WINTER PRUNING TIPS
Holly. The branches on holly (in the genus Ilex) can often be long and lean, and cutting them back by a quarter to a third of their length will help the plant to be bushier. This can be done just about any month of the year but in December the plant gets shaped and you can use the clippings for Christmas decorating.
Shrubs. Shrubs that are in the genus Taxus can also be pruned throughout the year. Some people prefer to shear yews into formal shapes and hedges, but others clip them by hand to keep a more open, natural form. These plants can be lightly pruned in the winter but if you’re planning to cut off more than half their size for a renovation pruning, wait until April or May.
Arborvitae. The foliage of all the arborvitaes (in the genus Thuja) makes wonderful cut greens for wreaths, swags, and holiday flower arrangements. But you need to be careful not to cut these plants back too far. Arborvitae doesn’t grow back from bare stems like other evergreens such as yews or holly. If you cut an arborvitae so that the interior, bare stems are exposed you’ll always have an empty place on that plant. Any clipping should be mid-way on the branches so that there is always green foliage left below the cut.
Junipers. Although junipers can be pruned in December they require thoughtful cutting to keep them attractive. It’s the long, tapering and feathery branches that make these plants beautiful; chopping those off can destroy their appearance. If a juniper is growing so wide that it’s blocking walkways, driveways etc., the way to reduce the plant’s width is by following those long, older stems way back into the center of the plant where they originate, and making the cut there. Avoid shearing junipers whenever possible.
White Pines. The greens from this native tree are prized for Christmas decorating, so by all means clip off branches from twelve inches to two feet long. But if you want to thicken the growth of young white pines the time to clip them is when the new growth is about six inches long. Watch your plants in May and when those straight “candles” are new but have not yet opened into needles, cut them in half. When this type of pruning is done to young white pines they become much more dense and bushy.
Evergreens. What about other evergreens? In general, any needled plants that don’t have showy flowers can be pruned now. Avoid trimming plants that flower in the spring such as Rhododendron and Pieris.
So take advantage of a sunny winter day and go out with your pruners. With these winter pruning tips, you’ll be ahead of the game in the spring, and will have lovely fresh greens for filling window boxes or other holiday decorating.
C.L. Fornari
C.L. Fornari is the author of The Cocktail Hour Garden (St. Lynn’s Press, 2016) and several other books. She hosts gardening programs on WXTK and WRKO and gardens on Poison Ivy Acres on Cape Cod. Learn more about C.L. on her site, gardenlady.com.