Boxwoods have been in recorded history since 4000 B.C. when the Egyptians first used them in formal gardens.
They came to North America from Europe and Asia in the mid-1600s. The American Boxwood Society calls boxwoods “man’s oldest garden ornamental,” and National Boxwood Collection at the United States National Arboretum in Washington, D.C., houses the most complete living collection of boxwoods.
They’re a big deal and have been for some time.
In Louisiana landscapes, littleleaf boxwood is heavily used. It is a thick evergreen shrub, native to Japan, that can be shaped into a low hedge and used as a foundation planting around the house.
Boxwoods have shallow roots, growing best in moist, cool soils in full to partial sun. The shrubs grow slowly and require some nurturing to become established. They need to be protected from heavy winds, cold and heavy sun when first growing. Water well in the first few weeks and use mulch.
There are many cultivars available, such as:
- Compacta, which is very small and compact;
- Green gem, which has dark green foliage;
- Green mountain, which grows upright at a moderate rate, has a conical form and small leaves;
- Winter beauty, a mounded form with dark green leaves that go bronze in winter;
- Var. koreana, which is compact, cold hardy and spreads more with dull green leaves;
- Sunnyside, which has larger leaves with good cold hardiness and is fast growing with some bronzing in the winter;
- Wintergreen, which has bright green leaf color and small leaves.
All that said, boxwoods do have some issues — pests and plant diseases, such as macrophoma, volutella blight and phytopthera root rot.
And then there is the dreaded boxwood blight disease, caused by calonectria pseudonaviculata, first seen in the U.S. in 2011. Infected plants display brown lesions on the leaves and dark cankers on the stems. If not addressed, the disease can lead to defoliation and death. Once infected, there is no cure. Fungicides may reduce the chances of infection. Other practices to decrease the chance of infection include proper spacing, watering at the base of the plant, removing diseased leaves, sterilize pruning equipment and rotating fungicides to avoid resistance.
Another major concern with boxwoods is boxwood dieback, first described in 2015 by Raghuwinder Singh, a scientist from LSU. Caused by a fungal pathogen, the disease causes foliage and branches to dieback leading to the trademark tan foliage that stays attached to the branches. An additional symptom is black discoloration of the stem underneath the bark, when scratched back.
The disease is spread by spores disrupted by wind, irrigation water, rain and by infected pruning equipment. Because it is such a new disease, fungicide treatments are limited.
The good news is you can get the look and design, without all the problems, of boxwoods with look-alike plants.
Some options are dwarf yaupon holly and inkberry holly, both native plants so they're adapted to our climate and are less susceptible to disease and pests.
You can also try other evergreens with coarser-textured leaves, such as distylium, dwarf arborvitae, podocarpus, waxmyrtly, carissa holly and pittosporum to name a few.
I am not trying to discourage folks from using the classic boxwood shrub that's been around for centuries. But I do think there are some interesting alternatives for a time when these disease issues are a real concern.