Endless Summer mophead hydrangeas are in the Hydrangea macrophylla family, but they offer what other members of this family do not. Endless Summer hydrangeas bloom on new and old wood, so they have large, showy blossoms repeatedly during the summer months. Depending on the acidity or alkalinity of the soil in your garden, these hydrangeas may have blossoms that appear in shades of pink, blue and occasionally white. Endless Summer hydrangea grows easily in zones 4 through 9.
Select an area in your garden or yard that receives morning sun. If you live in a northern climate, hydrangeas can withstand more sun, but southern growers should select a spot with afternoon shade. Test the soil to determine pH levels. Hydrangeas prefer soil that is slightly acidic, with pH levels between 4.5 and 6.5.
Dig a hole that's 1 1/2 times as wide as the growing container. The hole should be as deep as the growing container. Remove the hydrangea from the container and loosen the soil on the sides and at the base with your hands. Center the hydrangea in the hole so that the top of the root-ball is at ground level. Fill in around the hydrangea with soil. You can mix in potting soil or organic compost to enrich your garden soil around the plant.
Water the soil around the hydrangea thoroughly after planting. If the soil sinks down after watering, add more soil around the plant and water again. Add 2 inches of bark mulch around the plant for moisture retention, but do not let the mulch touch the stem. Keep your Endless Summer hydrangea moist in hot weather. Water daily as needed.
Fertilize your Endless Summer once during the spring before the plant blooms. Spread or pour the fertilizer around the drip line of the hydrangea branches, not close to the trunk.
Deadhead Endless Summer hydrangeas in the spring, before the new blossoms begin. You can leave spent blooms on the plant during the winter to help protect new buds. Cut the flowers during the season to enjoy in arrangements or to dry for crafts.