Thursday, November 7, 2013

Rough Year for Boxwoods in Cobb County

Recently, we have seen a lot of troubled Boxwood shrubs, brought in by County residents, here at the Cobb County Cooperative Extension office. Several samples have been sent to UGA's pathology lab, and although a couple of reports have listed disease pathogens such as Volutella as causing some of the trouble, others have cited root problems as the likeliest cause of decline for the sample.

In particular, wet conditions (remember all that rain we had in spring and early summer?) leading to root decay was noted in more than one report.

Virginia Cooperative Extension's publication Selecting Landscape Plants: Boxwoods explains how to select, plant, and care for Boxwood shrubs, and it includes this information about tolerance of Boxwoods to moist soil conditions:
"Boxwoods can grow in a variety of soil textures (relative amounts of sand, silt, and clay), but too much sand (a low water-holding content) or too much clay (too high a water-holding content and too low an air-holding content) should be avoided. A soil that is well-drained is essential; thus, low areas of the landscape that tend to stay moist or wet do not support boxwood growth."
In other words, Boxwoods are not at all tolerant of soil that doesn't drain well and that stays wet for extended time periods. If more Boxwoods out there are struggling, a closer look at the soil conditions might show that poor drainage is part of the problem.

In addition to being a little bit finicky about soil conditions, Boxwood shrubs here in North Georgia have a full measure of pest and disease problems, but Virginia Cooperative Extension's Boxwoods information page notes that deer typically don't eat boxwood, making it an attractive choice for neighborhoods that are troubled by deer.

For those whose Boxwoods are not doing well right now, Clemson University's publication Boxwood Diseases and Insect Pests contains helpful descriptions and photos of commonly seen Boxwood problems.

UGA's Landscape Alert October 18 blog post Boxwood Blight Update by pathologist Jean Williams Woodward tells about a fairly alarming new Boxwood Blight that has not yet made it to Georgia. The update (click on the linked title to see the original blog post) contains photos and a full description, along with tips that can help keep this disease out of our landscapes. This is the "bottom line" in preventing the spread of this fast-moving disease:
"You won’t get this disease if you don’t bring in any boxwoods. The spores are not wind-borne; they are water-splashed and carried on plants, people, tools, and animals. If you do bring in boxwood plants, make sure they come from a nursery certified to be free of Boxwood Blight."
Specifically, to reduce the spread of this disease, Woodward suggests disinfecting tools that are used on or around Boxwoods and considering propagating your own plants from Boxwoods that are known to be free of this new Blight.

For all Boxwood problems, prevention through appropriate variety selection and careful planting-site preparation and maintenance practices are key to our being able to enjoy healthy, beautiful plants in our landscapes for years to come.