Winter’s Gems: Boxwoods

Posted: 2018 | Spring | Tree and Shrub Planting

The role evergreens play in the landscape has always been a prominent one. Their beauty often frames the remainder of the landscape, home, prominent features, or are some of the prominent features themselves. Evergreens are a favorite and all the more so in the bleak months of late fall, winter and early spring. And all the more so in the North, where the bleakness of these months are the most needful of evergreen life.

Everyone is very familiar with the “needle” evergreens (spruces, firs, pines, arborvitaes and junipers) and some of these grace nearly every yard. But there is another group that is not as common. They are the “broadleaf” evergreens – they actually have regular “leafy” leaves that stay green for most or all of the winter. Some examples are: select Holly cultivars, Euonymus, Daphne, and Pachysandra. A group of small shrubs known as Boxwoods have risen greatly in popularity over the last several years. They are broadleaf evergreens as well. Although known and used for many years, some of the older cultivars were prone to winter damage and were kind of delicate. The newer cultivars have performed very well, showing little winter damage, if at least some thought in placement and siting is accommodated.

Boxwood can be pruned to stay in bounds of their intended space, or to form continuous hedges, bed borders, or even to take on shapes (in Europe, for instance, they are often trained into formal shapes or “topiary” – including animal shapes [watch out for Edward Scissorhands!]) This ability enables them to conform to nearly any space. They have many small evergreen leaves and are very dense, allowing them to hide air conditioners, meters, pipes, building foundations, etc. They actually need very little pruning and I think their beauty emerges more fully if informally pruned, retaining the natural “feathery” look, yet not looking unkempt.

With all of these beautiful attributes to recommend them, their use has exploded over the last decade. There are a few insect and disease issues to be aware of:

Boxwood Leafminer – this insect mines out the interior of the leaf (very small larvae), leaving them browned and unsightly. It can multiply fast over a few years, turning a green hedge into a brown one. It has become the most important insect pest of boxwood in our area. Fortunately, it is easily controlled either by a carefully timed spray application or the use of soil systemic insecticides.
Boxwood Psyllid – the small fly-like insect lays its eggs into the leafy tip growth. The feeding of the larvae causes the end leaves to curl, giving the plant a “balled-up” look over time. Many people to not notice this damage unless it is pointed out to them. The damage is extremely common but is mostly cosmetic. However, it can be controlled to improve the appearance if desired. Again, either timed sprays or soil systemic insecticides work well.
Boxwood mite – is a relative of the spiders and require the use of a miticide spray when there is an outbreak. However, this is not seen at problem levels too often. Their damage includes an increasing amount of “bronzing” of the foliage as leaf feeding continues. If damage gets too heavy, loss of plants can occur.
Volutella/Phytopthora complex – is a combination of fungal diseases that often work together to slowly kill roots and the lower woody stems. This one is the most serious of the boxwood problems and eradication is not possible. Successful management is often possible through the use of certain soil fungicides. When diseased plants and diseased portions of plants are removed (sanitation) and a fungicide program is employed, many years of serviceable plants can result. This is most helpful when a property has committed to many boxwoods (example – using them to border and define a “knot garden”). It is not a curative situation, but has proved very helpful in maintaining larger plantings.

These wonderful plants will continue to be used in a variety of ways including replacing some of the yews and junipers that have been used in “cookie-cutter” fashion for many decades to form the front foundation of many dwellings and businesses. Although few plants are “bullet-proof, “boxwoods are generally shrubs requiring low maintenance.

Call your Wachtel Certified Arborist if you have any problems showing up on your boxwoods, or if you would like to add some of these delightful plants to your yard!