Annabelle Hydrangea is a variety of smooth, fast-growing hydrangea. It produces large white flower clusters that are approximately 1 foot across, blooming throughout the summer and fall. The bushes grow to be 3 to 5 feet tall and about as wide. They are cold hardy in USDA hardiness zones 4 to 9.
Plant Annabelle hydrangeas in the fall or early spring. Plant them in a location with afternoon shade. Dig a hole that is approximately 2 feet wider and the same depth as the rootball. Mix the soil from the hole with an equal part of organic compost.
Place the plant in the hole and backfill with the amended soil. Create a mound in areas with poor drainage, lifting the plant above the natural soil level.
Apply a 3-inch layer of organic mulch under and around the hydrangea to help conserve water and shelter the roots from the heat.
Water Annabelle hydrangea during hot, dry weather. Provide 1 inch of water per week when rainfall is insufficient.
Apply a balanced fertilizer such as 10-10-10 at a rate of 1 lb. per 100 square feet in late winter. Water thoroughly after applying fertilizer.
Remove dead and fading flowers. Deadheading stimulates new flowers and keeps the hydrangea looking tidy.
Prune the plant to within 6 to 12 inches of ground level in late winter or early spring. Annabelle hydrangea bloom on new wood. Pruning the plant back will stimulate new growth and more flowers.