Panicle hydrangeas have become the darlings of the hydrangea family, and for good reason. Their conical-shaped flower clusters bloom on new wood and are not subject to tough winters or the previous season’s pruning faux pas. But shopping for a panicle hydrangea at your local nursery can be overwhelming, with a host of varieties vying for your attention and dollars. Which is best suited to your location? Which will sport the best foliage and flowers? The panicle hydrangea trial at Secrest Arboretum, in its fourth of five years of data collection, will provide solid information for making those purchase decisions. The trial’s evaluation of pruning methods will guide post-purchase care.
Undertaking a five-year, comprehensive trial requires strict adherence to the scientific process, and hundreds of hours of data collection. A team of Secrest Master Gardeners is on the job, with a weekly visit to each of the 207 panicle hydrangeas (3 each of 69 cultivars) in the study. Using electronic devices, they record each plant’s phenology (at what point are they in growth and flowering), floral coverage, flower color transition to pink, flower browning, susceptibility to heat scorch, scent, foliage quality, diseases, pests, and the presence of pollinators. Each of the three cultivar replications undergoes a different pruning regimen (basal, 50%, or no pruning) to help determine the most effective pruning strategy. The concluding rankings will be based on an aggregate of the average scores over the trial. Gardeners will be able to note the best performing cultivars and their qualities. Equally important will be the ones to avoid.
Obtaining data over a five-year time span helps eliminate the vagaries of differing weather patterns and pest and disease challenges. In the end, the study’s report will help Ohio homeowners and landscapers break through the marketing hoopla and multitude of options and choose the best panicle hydrangea for their particular needs.
Visiting the trial garden during the bloom season is a visual and olfactory treat*, and wandering down the rows of hydrangeas allows an in-person observation of superior and inferior cultivars. If you come upon this year’s data collection team, Master Gardeners Karen Lesiecki, Dave Stilwell, Deborah Hefling, and their alternates, you might ask them about their current favorite. They know which panicle hydrangeas are butterfly or bee magnets, and which have the most beautiful colors. They’ve seen the results of the three different pruning methods first-hand.
Master Gardeners are key to Secrest’s success as a living educational and outreach resource. Look for them behind the scenes: maintaining the garden beds, working in the greenhouse, and assisting with research.
* The Secrest Arboretum hydrangea trial is located directly across the street from the Welcome and
Education Center.
–Karen Edgington, Master Gardener Volunteer