Abstract

Hydrangeas are popular seaside plants; however, other than in anecdotal reports, there are no studies measuring their relative tolerance to salt spray. We examined response of ten cultivars and one subspecies of Hydrangea representing five species to foliar-applied salt solutions to recommend selections for seaside landscapes. Objectives were to determine whether there are differences in responses to salt spray among cultivars and species, and to determine whether varying concentrations of sodium chloride differentially damaged the plants. Plants were treated with a full-strength (ion concentration approximate to seawater) salt solution, a half-strength salt solution, or a control of tap water. Plants were rated after seven once-weekly applications based on percentage necrotic leaf area, an aesthetically and physiologically important symptom of damage. Cultivars of Hydrangea macrophylla and Hydrangea serrata were more tolerant of full-strength salt spray than cultivars of H. paniculata, H. anomala and H. arborescens. At half strength but not full strength, H. anomala ssp. petiolaris was most tolerant. Hydrangea macrophylla and H. serrata were the second most tolerant of half-strength applications. Hydrangea macrophylla or Hydrangea serrata should be planted where maritime salt spray will occur.