After five years of study, Mt. Cuba Center releases Wild Hydrangea for the Mid-Atlantic Region, its latest research report evaluating 29 species and cultivars of this popular native shrub. Sam Hoadley, manager of horticultural research, evaluated Hydrangea arborescens and its relatives Hydrangea cinerea and Hydrangea radiata on horticultural merit, adaptability, and ecological value.
“Hydrangea arborescens are a classic landscape shrub that is currently undergoing a garden renaissance,” says Hoadley. “Their beauty, cultural adaptability, and ability to support wildlife make them a welcome addition to any garden in the mid-Atlantic region and beyond.”
The variety of H. arborescens cultivars continues to grow and enables broader use in more horticultural niches thanks to ornamental breakthroughs. Cultivars are plants that are selected or bred by humans for desired traits such as sturdy stems and new flower forms and colors. The introduction of hydrangea cultivars selected or bred for ornamental purposes raises questions about their ability to support wildlife, however, and this trial answers these questions by tracking pollinator visits.
- The results show, with few exceptions, that lacecap hydrangeas are much more frequently visited by pollinators than mopheads. Mt. Cuba’s Pollinator Watch team, a trained group of volunteer citizen scientists, observed and recorded the number of pollinating insects visiting each of the 29 hydrangeas grown in full sun during 2019 and 2021.
- Lacecap flowers are the predominant flower form in wild arborescens and contain hundreds of fertile flowers, usually surrounded by a ring of showy sterile flowers. Mopheads contain masses of sterile flowers in large, often dome-shaped flower heads, with relatively few fertile flowers.
- Hydrangea arborescens ‘Haas’ Halo’, the top performer in this trial, is a cultivar offering both horticultural excellence and pollinator value.
- This cultivar produces exceptionally large and showy lacecap inflorescences that have proven to be highly attractive to insect pollinators.
- Hydrangeas do better in shade when grown in the Mid-Atlantic region. The evaluation was conducted in full sun, and 19 plants were also grown in 60 percent shade for comparison.
- Cutting back plants often reduces the overall height and width of the shrub while increasing the diameter of the flower heads.
This report reveals Mt. Cuba’s top nine horticultural performers and five honorable mentions. Detailed research reports from all of Mt. Cuba’s trials, and descriptions of all 29 plants included in our Hydrangea arborescens trial, are available on our website: mtcubacenter.org/trial.
Mt. Cuba’s Hydrangea arborescens Top Performers:
- Hydrangea arborescens ‘Haas’ Halo’
- Hydrangea arborescens ‘SMNHALR’ (Lime Rickey®)
- Hydrangea arborescens ‘NCHA2’ (Invincibelle® Spirit II)
- Hydrangea arborescens ‘NCHA4’ (Incrediball® Blush)
- Hydrangea arborescens ‘Abetwo’ (Incrediball®)
- Hydrangea arborescens ‘Bounty’
- Hydrangea arborescens ‘Dardom’ (White Dome®)
- Hydrangea arborescens ‘Total Eclipse’
- Hydrangea arborescens ‘Mary Nell’