Boxwood is one common type of shrub found in many public and private gardens everywhere. Boxwood shrubs are very versatile and can be used as hedges, parterres, individual, or even in containers or topiary. While most people think there are merely two types of boxwood—American and English—there are actually around 160 different cultivars. Of these 160 there are around 115 available commercially to you.
Boxwood is considered a simple, low-maintenance shrub overall, but there are some general guidelines to follow when planting boxwood shrubs. The fall season is the ideal time to plant boxwood. Any pruning or thinning that needs to be done is best in the winter. Boxwoods can also be planted in the spring and summer with special attention paid to protecting your plants from insects and keeping them well watered. For best results use a soft or clay soil.
1. Insects and Disease
Insects and disease to worry about will typically vary depending on the type of cultivar you choose. The most common pests include mites, leafminer, as well as psyllid. Any of these pests need to be treated as soon as possible if infestation is severe. There are also types of fungi that may infect boxwood, however they are not normally a serious issue. Only a few types of boxwood have experienced any decline and the threat is not nearly as severe as it was in the past. Most animals will not feed on boxwoods because of the toxin alkaloid they reportedly contain.
The most commonly used method to propagate boxwood shrubs is stem cutting. This method will give you new shrubs identical to those from which you took the cutting. The cuttings should, for best results, be taken from the one-year old parent plant between July and December and put into a container with the appropriate mix of soil and fertilizer. The roots will develop in two to three months. You can plant seeds directly or layer the roots, but both methods may yield slightly different variations of your boxwood.
3. When to Fertilize?
There is no set method as to when or how often you must fertilize your boxwood shrubs. The most specific way to determine the best results is to have the soil professionally tested. The simpler method is to look for indications of nitrogen deficiency in the boxwood. The first sign of nitrogen deficiency is the yellowing of the lower older leaves. Leaves will typically last on boxwoods for three years. If you notice them dropping earlier, that may also indicate a nitrogen deficiency and indicate a need for fertilization.
The best type of fertilizer to use on boxwood shrubs is a granular with a 10-6-4 or close analysis. The best time to apply fertilizer is in the late fall to get the best results of growth. Surface application around the baseline of the shrubs is the quickest and easiest method to apply fertilizer. For best results and to avoid over fertilization, try to apply the fertilizer when the soil is moist and over mulch if possible.