The Best Hydrangea for Sun

Species

• The best hydrangea species for full sun are the panicle hydrangea (Hydrangea paniculata) and the oakleaf hydrangea (H. quercifolia). This does not preclude the use of other species, including the bigleaf hydrangea (H. macrophylla) in sunny gardens, but the panicle and oakleaf types are the most tolerant of more sunlight and less finicky in that environment. Numerous cultivars exist of both species, increasing the options available for flowering time, flower cluster size and mature shrub size. Grow panicle hydrangea in U.S. Department of Agriculture plant hardiness zones 3 through 8 and oakleaf hydrangea in zones 5 through 9.

Regional Insight

• In northern parts of the United States, and where summers are relatively cool, most hydrangeas grow well in nearly all-day sunshine without detriment. Shade, especially in the afternoon, is much more important in areas where the summers are long and hot, or rainfall and humidity are low. Not all hydrangeas are appropriate for all parts of the United States. Brutally cold winters can kill or stunt certain species, but not harm others; the panicle hydrangea is more winter-hardy than the oakleaf and bigleaf hydrangeas, for example. Hydrangeas also need a winter dormancy, and are therefore not a long-term plant for subtropical or tropical regions.

Improving Sun Tolerance

• While some afternoon shade is beneficial to the most sun-tolerant panicle and oakleaf hydrangeas, all-day sun is better if the soil conditions are consistently high quality. Any hydrangea grown in an evenly moist, well-drained soil that is rich in organic matter grows better in sun than one in a dry or nutrient-poor soil. Amend both sand and clay garden soils with lots of compost and rotted manure before planting panicle and oakleaf hydrangeas. Also mulch the soil to a depth of 3 or 4 inches, as the mulch conserves soil moisture and shades and cools the soil during the heat of summer and in the sunny afternoon hours.

Water

• Moist roots offset the heating, drying effects of too much sun in hydrangeas. Never overwater a hydrangea so the soil is soggy or flooded, as it leads to root rot and fungal diseases. Irrigate as needed to supplement rainfall to maintain an evenly moist soil. Sandy soils require more frequent watering than loam and clay types. Full-sun exposures increase the need for a moist soil. Otherwise, the hydrangea leaves scald, get yellow or brown edges, or abort leaves in an effort to conserve moisture within the plant.