Valued by ancient civilizations for its beautiful close grained wood and evergreen foliage, boxwood has acquired legendary status during its 6,000 year history of use. It is one of the oldest plants cultivated by man for ornamental as well as commercial purposes.
The “bones” of the formal parterre garden here at the estate are boxwood, lovingly planted during the 1800’s by Mrs. Sarah Ferrell. We believe that she probably began her garden by rooting plants from shrubs in her mother Nancy’s garden, which was close by. Using primarily Buxus sempervirens ‘Suffruticosa’ (known as English or dwarf English boxwood) and Buxus sempervirens (common boxwood), she designed and created a magnificent terraced landscape reminiscent of a fine European garden. Other species and cultivars of box have been added to the garden over the years, so that now we have at least a dozen types representing at least five different species growing here. Due to both the popularity of boxwood and their prominence in our garden, it is natural that questions are put to us about the culture and care of these shrubs. Following are some of the most common inquiries that we receive along with answers from our horticulture staff for their successful cultivation in most of the Southeast.
Q: Are boxwood difficult to grow?
In general, no they are not. However, boxwood are like most plants in that they perform best where well sited and when their cultural requirements are given a reasonable amount of consideration.
Q: What sort of siting is preferred and what soil requirements are necessary in order for them to thrive?
Although boxwood will grow in full sun, situating them under high shade or where they will receive primarily morning sun and afternoon shade is more ideal. Avoiding exposure to large amounts of winter sun and wind is also advisable. Good soil drainage is a must, and extremely heavy clay or very sandy soils frequently cause problems. The correct soil pH is absolutely critical as boxwood thrive best in neutral soils with a pH from 6.5 (slightly acidic) to 7.5 (slightly alkaline). Due to the fact that soils in the South are typically acidic, we strongly advise having a sample done to test your soil’s pH and then amending to adjust it if necessary. We test the soil in the garden here at least once a year and usually have to apply lime annually in order to keep the soil from becoming too acidic for the boxwood.
Q: What is the best time of year to plant boxwood?
In our experience, fall, and specifically October, is the ideal time for us to plant. The month would vary depending on the part of the Southeast you live in.
Q: What about fertilization?
When we fertilize the garden, a light application of an organic fertilizer is broadcast over the entirety. In other words, we do not fertilize our boxwood separately unless it is a new planting or we observe signs of a nutrient deficiency or stress. We apply it every two or three months—even in the winter, although very lightly then. We also try to put compost around our boxwood once every year or two in order to protect their shallow roots and add humus to the soil. Our recommendation would be to tailor a similar fertilizer regimen for your boxwood if they are incorporated into a garden, as most of ours are. If they are being used as a foundation planting around your home, then fertilizing them individually might make more sense. However, we would still recommend organic fertilizer as well as periodic applications of some compost.
Q: What about using cottonseed meal on boxwood? Isn’t it a popular choice?
Yes, cottonseed meal has long been recommended for boxwood, and it is an excellent organic fertilizer. A warning about using cottonseed meal repeatedly—it will contribute to soil acidity (low pH) over time, which can certainly jeopardize the health of boxwood. Annual soil testing in order to monitor proper soil pH levels would be a must.
Q: How often do you water boxwood?
The answer to that question depends on several factors. As a rule, we like for our established boxwood to receive an inch of water (rain, preferably) about every ten days. We typically have to supplement with irrigation only during the summer. It is just as important for the plants not to be too dry during very cold weather as it is during hot weather, so being aware of rainfall amounts year round is very prudent. Newly planted boxwood, as with most shrubs, require more watering until established. Usually we water recently planted shrubs two or three times per week, particularly during their first spring and summer, depending on rainfall and temperature. Extra watering for newly planted boxwood is continued for a couple of summers, although not quite as often after their first full season of growth.
Q: What about insects and diseases?
Healthy boxwood are not typically bothered by serious disease problems. Siting them properly is more than half the battle in that regard. Also, if they are being sheared regularly, as in a formal garden such as ours, they need to be thinned periodically in order to prevent disease problems from occurring. Thinning involves cutting out small clumps of branches in order to let light and air into the interior of the shrub. The primary insect problem that we encounter is boxwood leaf miner, but not all boxwood fall victim to it. English as well as the many choices of Asian boxwood are quite resistant. However, common box and many of the hybrids are susceptible. The leaf miner’s presence is characterized by small round blisters on the underside of the leaves. If miner infestation is moderate to severe, treatment with a systemic insecticide will likely be necessary to reduce their numbers and control damage.
Q: Could I grow the same kinds of boxwood that you have growing at Hills & Dales?
If you live in the piedmont region you could grow most of the boxwood featured in our garden, including the predominant English and common box. In our opinion, the latter two do not thrive in southeastern zones that are warmer than USDA zone seven. Species native to Asia and their cultivars, as well as some hybrids do very well through zone eight and perhaps even further south. Examples are: Japanese boxwood (B. microphylla variety japonica), Harland’s boxwood (B. harlandii), and several cultivars of littleleaf boxwood (B. microphylla). Some of our favorites are: ‘Winter Gem’, ‘Curly Locks’ and ‘Green Mountain’ which is a hybrid. Several of the hybrids are quite vigorous in hot climates and have more of the Old World boxwood “look” than do many of the Asian ones.
Considered through the ages as garden classics and aristocrats, these shrubs have long had a secure place in the hearts, as well as the property of many southern gardeners. Mrs. Alice Callaway once wrote of those lining the paths and beds here at Hills & Dales as “cherished old plantings of boxwood.” Perhaps that thought, as well as the information we have given, might inspire you to plant this old-time favorite in your garden.