Summary

Mt. Cuba Center’s native hydrangea trial evaluated Hydrangea arborescens and its relatives Hydrangea cinerea and Hydrangea radiata. These three species bloom on new wood, which means that flower buds are produced when the plants are actively growing in the spring and early summer. As a result, they can be pruned from fall to early spring or even killed to the ground in extreme cold, and flowers will still be reliably produced in June and July.

The inflorescences of H. arborescens and its close allies fall into two categories: lacecaps and mopheads. Lacecap inflorescences are the predominant flower form in wild H. arborescens and contain hundreds of fertile flowers which are usually surrounded by a ring of showy sterile flowers. Mopheads, on the other hand, contain masses of sterile flowers in large, often dome-shaped flower heads, with relatively few fertile flowers hidden within.  The combined effect of the sterile flowers results in a spectacular ornamental display which contributes to the popularity of mophead hydrangeas in gardens.  Most hydrangeas in the trial bloom for just a few weeks in early summer, but the flower heads remain attractive through late summer and fall and add ornamental interest to winter landscapes. H. arborescens flowers are primarily white with several pink blooming cultivars that have been released in recent years.  Unlike the color-changing inflorescences of the non-native Hydrangea macrophylla and Hydrangea serrata, the flower color of the native species does not change depending on the acidity, or pH, of the soil in which they are gown.

The introduction of hydrangea cultivars selected or bred for ornamental purposes raises questions about their ability to support pollinators and other wildlife. Mt. Cuba Center’s trial aimed to answer this question by studying pollinator visits. We also evaluated maintenance strategies and the effect of growing hydrangeas in sun and shade.

The best performing hydrangea included in the trial are Hydrangea arborescens ‘Haas’ Halo’, Hydrangea ‘SMNHALR’ (Lime Rickey®), Hydrangea arborescens ‘NCHA4’ (Incrediball® Blush), Hydrangea arborescens ‘NCHA2’ (Invincibelle® Spirit II), Hydrangea arborescens ‘Abetwo’ (Incrediball®), Hydrangea arborescens ‘Bounty’, Hydrangea arborescens ‘Dardom’ (White Dome®), Hydrangea arborescens ‘Mary Nell’, and Hydrangea arborescens ‘Total Eclipse’.

Click here to view the research report in full screen, or scroll down for detailed descriptions about the performance of each plant in the evaluation.

Download this sortable Excel spreadsheet with each species and cultivar from our Hydrangea trial, sun conditions, height, spread, bloom color, and bloom period. Try utilizing Excel’s “Filter” feature to sort plants by these characteristics.

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