Resource Expands HRI’s Growing Boxwood Blight Library

The Horticultural Research Institute (HRI) released a set of recommended best management practices (BMPs) aimed at dealing with boxwood blight in the landscape. The new BMPs came at the request of industry stakeholders following new findings from ongoing boxwood blight research.

As boxwood blight discoveries continue to increase, so does concern over the long-term success of the most popular broadleaf evergreen, boxwood. The BMPs are meant to provide guidance to landscape managers regarding practices and their risk of boxwood blight. They are suggested for voluntary adoption; none are mandatory or legally enforceable.

Topics address practices to help train personnel, the importance of scouting, reducing the risk of introduction to a property, preventing spread of a confirmed infected area, replanting, and sanitation. All recommendations were developed by a working group convened by HRI consisting of National Plant Board representatives and landscape managers. Furthermore, the National Association of Landscape Professionals (NALP) endorsed the resulting BMPs.

“Boxwood blight continues to grow as a threat to established landscapes across North America,” states Gary Knosher, HRI President. “Boxwood is the most popular broadleaf evergreen sold in the United States and has significant presence in landscapes and historic gardens. Creating voluntary management practices for boxwood health to guide landscape managers was a natural next step in HRI’s commitment in helping the industry mitigate the spread of the disease.”

The current BMPs for nursery production were updated as well to reflect more recent findings by the research community. For example, 70% alcohol has been confirmed to kill conidia, a type of spore, within seconds. This is a critically important and cost-effective tool to incorporate into sanitation practices such as cleaning pruning tools between blocks and/or properties.

HRI is invested in helping the industry understand the complex nature of boxwood health. To aid growers, we partnered with the Oregon Association of Nurseries and hosted a one-day, sold-out workshop in February 2020. The workshop emphasized the importance of BMPs and cultivar selection to best managed boxwood blight. Presentation materials from this workshop are available here.

HRI proudly supports scientific research and students for the advancement of the environmental horticultural industry. Outreach is a key component to HRI’s mission. HRI was established by industry leaders on the premise that no one could better direct needed research to advance horticulture than the very people who work in it, day in and day out.

The Horticultural Research Institute (HRI), founded in 1962, has provided more than $7.5 million in funds to research projects covering a broad range of production, environmental, and business issues important to the green industry. Nearly $11 million is committed to the endowment by individuals, corporations, and associations.