Tips to Keep a Hydrangea From Wilting

Light

• Most hydrangeas thrive as understory plants, sited underneath trees. They enjoy partial shade with filtered sunlight. Morning sun and afternoon shade offer optimal light conditions for bigleaf hydrangeas (Hydrangea macrophylla). Overexposure to sun causes the leaves to wilt, and full sun causes leaf scorch and plant stress. Paniculata hydrangeas tolerate more sun than bigleaf hydrangeas, but they still benefit from afternoon shade in the South.

Water

• Overhead irrigation systems, such as automatic pop-up sprinkler heads or oscillating lawn sprinklers, do not provide the deep watering that hydrangeas need. They also create a favorable environment for fungal leaf diseases, such as cercospora leaf spot. A tip for providing adequate and deep watering to keep hydrangeas from wilting is to install soaker hoses, or weep hoses, around hydrangea shrubs. Mulching on top of the soaker hoses slows evaporation and keeps water around the root zone instead of on the foliage.

Soil

• Hydrangeas wilt when planted in poor-quality soil even if additional water is provided. As understory plants, hydrangeas must compete with tree roots for water and nutrients. Sometimes the best way to keep a hydrangea from persistent wilting is to transplant it to a different location with better-quality soil and minimal root competition. Applying a 2- to 3-inch mulch cover helps retain moisture. Pine straw and finely shredded pine bark are preferred acidic mulches that enrich poor soil as they decompose.

Disease

• Armillaria root rot, or mushroom root rot, and phytophthora root rot are fungal diseases. They attack oakleaf hydrangeas most commonly, although other hydrangea species are susceptible. Armillaria fungi cause sudden wilting of plants. Gardeners suspecting insufficient water will irrigate plants to no avail as leaves on infected plants will not revive after watering. Plant mortality can occur within a few weeks. Phytophthora also causes sudden wilting of foliage. In their attempts to revive wilted plants, gardeners exacerbate the progression of this disease by providing too much water.