Nancy Brachey

Some plants benefit from winter pruning

A nandina that has grown leggy over time can be encouraged to thicken up and become more dense with winter pruning.
A nandina that has grown leggy over time can be encouraged to thicken up and become more dense with winter pruning. Observer file photo

At mid-February, we start to think about pruning shrubs. Not all shrubs, mind you, but certain ones that benefit when pruning is done in late winter, just ahead of spring growth.

This excludes many of our most popular landscape plants, including azaleas, forsythia, rhododendron, pieris, and spirea, which bloom in spring. Pruning before they bloom will remove this year’s flowers and that will make you unhappy.

However, it is prime time for pruning many more evergreen landscape plants. This includes hollies, cleyeras, nandinas, boxwoods and ligustrums. Some may have merely outgrown their space a bit and are crowding their neighbors. Others may have been growing for years and you have finally decided to get them in shape.

The chief reason to do this work now is that it brings the plant to the right height, width and shape in advance of the new growth in spring. This fresh growth is the best year and it is a shame to lose it by untimely pruning later in spring or summer.

Well-established evergreens, notably hollies, nandinas and ligustrums, can take severe pruning if that is necessary for space or shape reasons. I have seen these plants cut well back and then recover over time to become nice plants. This is because they have well-developed root systems that will encourage fresh growth.

The conventional wisdom is to prune no more than one-third of the plant. Sometimes, more drastic pruning is desired. Pruning back to large branches may take a couple of seasons for the plant to recover and fully leaf out. Be prepared to live with that.

However, you could do this major pruning in stages of two or three years, cutting back one third each year until you get it right. Remember, a major virtue of a gardener is patience.

Before you begin either minor or drastic pruning, look over your plant and decide how far back you will cut it this year. Start with any wayward stems affecting the shape of the plant, and cut them back with pruning shears or long-handled lopping shears. As you continue thinning the plant, judge how it is looking, both in size and shape. Avoid cutting the plants, especially hollies, into small round shapes, often called meatballs, and it is not a compliment.

Some plants, such as nandinas, grow on rather long branches rising vertically and benefit from removal of the oldest stems cut close to the base of the plant, allowing space for fresh, new growth. A leggy nandina will thicken up in a season of growth because of its inherent vigor.

The small Japanese hollies with dense foliage benefit from a type of pruning called shearing when they are used as low edging plants around shrub beds. This means using hedge clippers to create a smooth, even surface across the top and sides to create a hedge effect. When new growth emerges evenly over this sheared plant, it looks quite lovely and creates a formal edge that many people like very much.

Nancy Brachey:

Ask Nancy

Q. My pansies don’t look so good after the recent stretch of ice and snow. What would help them?

A.Sunny cool days will help the pansies begin to grow again. Snipping off spent blooms and any damaged leaves will be a big help. A does of liquid fertilizer applied at the rate and time recommended on the package will encourage fresh growth and vigorous plants.