Hydrangeas are prolific flowering plants native to areas of Southern Asia and North America. Although there are more than 20 species of hydrangeas in existence, only five of them typically are grown in the United States. All five are well-suited for growing in areas of the South, including Alabama where the native oakleaf hydrangea is known as the state's wildflower. With the proper care, hydrangeas can thrive and bloom in Alabama gardens for many years.
Plant hydrangea in a well-drained growing site that receives full morning sun and partial afternoon shade. Optimize soil drainage by planting hydrangeas in a mixture of 50 percent garden soil to 50 percent organic compost.
Keep the soil consistently moist but not soggy. Give hydrangeas at least 1 inch of water per week through rain or irrigation.
Add a 1- to -2-inch layer of organic mulch around the base of the hydrangea to help conserve moisture and keep the roots cooler during the hot summer months.
Fertilize according to your particular hydrangea species. Give bigleaf hydrangeas light applications of a general purpose fertilizer such as 10-10-10, applied in March, May and July at a rate of 1 lb. per 100 feet. Give panicle and oakleaf hydrangeas applications of the same fertilizer in April and June, and smooth hydrangeas need one application of 10-10-10 in late winter.
Prune according to species. Prune bigleaf and oakleaf hydrangeas, which bloom on old wood growth, immediately after flowering. Cut away 25 to 50 percent of the old stems with a pair of pruning shears to improve the shape of the plants and increase flowering during the next season. Trim the smooth and panicle hydrangeas, which bloom from new growth, to half their height every year in late winter or early spring. Remove up to half of the stems on panicle hydrangeas in early spring to encourage more flowering.