Boxwood Blight - A 15 Year Love and Hate Relationship

HRI Research • March 29, 2021

German researchers have been working on boxwood blight since it first appeared in Germany in the summer of 2004. Initial cultivar trials indicated that there were large differences in susceptibility. This resulted in a series of horticultural trials, on the one hand on the susceptibility of Buxus species and cultivars, and on the other hand on alternative woody plants as substitutes for boxwood. In parallel, many trials on the suitability of fungicides have been running since 2005, both in vitro and in the field. In addition, the trials have repeatedly tested preparations that were considered as alternatives for chemical plant protection. Furthermore, we monitored the occurrence of the two blight pathogens, Calonectria pseudonaviculata and C. henricotiae, and examined other host plants - Pachysandra and Sarcococca in trials. This talk will summarize the 15-years of research results and share the successes and difficulties of blight control in gardens and parks in Germany.

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Bee Banquet in the Sky: Trees and Shrubs for Urban Pollinator Conservation

By Jennifer Gray • October 12, 2026

Urban landscapes can be important refuges for native bees and other pollinators. This talk covers why bees are critical for biodiversity and food security, why bee populations are declining, and how the gardening public can help by incorporating woody landscape plants to provide nectar, pollen, nesting sites and materials, and other resources. Following a brief overview of pollination ecology, we’ll “meet the bees”, and then discuss recent HRI-funded research that identified top native and non-native “bee magnets” amongst woody ornamental plants. The talk also explains why artificial bee “hotels” can become death traps and suggests better ways to create bee nesting sites through ordinary gardening practices. Attendees will receive PDF handouts and other information helpful for teaching others about the best trees and shrubs for bee conservation.

A Biological Plot Twist: Can an Adventive Parasitoid Protect Boxwood?

By Jen Gray • August 12, 2026

CABI and USDA APHIS are collaborating on the biological control of the box tree moth using parasitoids from Asia. Several parasitoid species are currently under consideration for introduction into North America and Europe. One of these parasitoids arrived in Europe on its own and has begun controlling the moth on both planted trees and in wild boxwood stands. The webinar will describe the spread and impact of this adventive parasitoid in Europe and present efforts to assess the potential of this species and others as biological control agents in North America.

HRI Leadership Academy Selects Class of 2027

By Jennifer Gray • June 30, 2026

Meet the HRI Leadership Academy Class of 2027. This intensive year-long program equips green industry leaders with strategic insight and business acumen.