Everything You Need To Know About The Korean Boxwood
There are roughly 90 species of boxwood, with American boxwood, English boxwood, and Korean boxwood among the favorites. The Korean boxwood is a variety of the Buxus microphylla species. Boxwood is a very popular landscaping plant, and is often grown either as a low hedge, or as a neatly trimmed border plant. Many species and varieties of boxwood can also serve as excellent specimen plants.
While most boxwood you will see in private gardens or in large landscaped areas, are carefully pruned, the plant is actually a rather low maintenance plant. Pruning will keep it healthier, but pruning is most often done to achieve and maintain a desired shape. Propagation of boxwood is often done from cuttings, as that method will guarantee the new plants that will be identical to the parent plant. When planted from seedlings, individual plants can sometimes differ from one another.
American, English, Or Korean
The most widely grown boxwood in the United States is the American boxwood, although it is not native to North America, having immigrated from England in the 17th or early 18th century. It is a taller shrub than the English boxwood, which in turn has a somewhat greater spread. The plant you eventually will buy depends of course upon what you are looking for, but you find it difficult to decide between an American or an English boxwood, the Korean boxwood would be a good compromise, as it is quite not as tall as the American boxwood, and not quite as wide as the English boxwood. It represents a kind of happy median.
Takes Well To Pruning
One of the great advantages the Korean boxwood has over its American and English counterparts is this. When the shrub becomes tight, which is to say the interior branches become closer and closer together, its branches still bear foliage, so the plant becomes very dense in its appearance, and is less likely to show gaps, or bare interior branches, when pruned back. The same cannot always be said for either the American or English boxwood. Some owners claim that with regular pruning or shearing, the Korean variety tends to become more and more dense. Pruning twice a year is generally recommended, and this variety tends to be a little more forgiving if one makes a mistake, such as cutting a bit too deeply, than is the case with most other members of the boxwood family.
Characteristics Of The Korean Variety
The Korean variety is a slow-growing plant, which typically reaches a height of from 2’ to 3' and has a spread that will vary from 4' to 5'. The species name, microphylla, means “small leaf” and this shrub has small, rounded leaves. It does bear clusters of small creamy yellow flowers, but they tend to be rather inconspicuous, and the plant is primarily grown for its attractive foliage. As the plant is an evergreen, it will retain its leaves throughout the year. An individual boxwood leaf typically has a life span of about 3 years before it drops off, and is replaced by another leaf. It's normal to see a few leaves fall from the shrub on a more or less continual basis. A significant leaf fall however might be a sign of trouble, either due to a pest, due to a disease, or a need to give the plant a high nitrogen fertilizer. In very cold climates, the leaves will sometimes turn a bronze color, while in more temperate regions they usually remain green. This variety is an excellent cold weather plant. It can be grown in Zone 4, a zone where many other boxwood species or varieties will fail. Its hardiness zones are generally advertised as being Zones 4 through 9.
Pests and diseases most common to boxwood are boxwood leaf miner, boxwood web worm, root rot, and boxwood mites. The Korean variety is more resistant to these diseases and pests than most other varieties. Root rot can be avoided by planting boxwood in a location where there is not likely ever to be standing water. This variety is considered to be moderately deer resistant, meaning deer will not seek the plant out, and they will usually not bother it when there are other goodies in the vicinity they can eat.
If you intend to plant the Korean boxwood as a specimen plant, give it at least 4' of space in every direction, with a 6' spacing being even better. When planting as a hedge or border plant, an 18'' spacing is recommended. These plants can grow in full sun or partial shade. If grown in full sun the plants should be mulched, since their root systems are quite shallow, and the roots need to be shaded from direct or strong sunlight. When mulching, it's best to leave a little space around the base of the shrub rather than simply piling the mulch up against the plant. Using too much mulch can result in a plant's root system becoming even shallower than normal, and consequently less able to withstand periods of drought. A good rule of thumb for mulching is a 2'' thickness, maximum.