Hydrangea is a genus of flowering shrubs beloved for their large blooms and rich green serrated leaves. Many species and cultivars of the shrubs are hardy in USDA zones 4 through 9 and hence grow well in most Midwestern states, save areas along the U.S. and Canada border. Hydrangeas like moisture, moderate sun, protection from frost, nutrient-rich soil and annual pruning to remove damage and weak growth. With care they will put on a good show in Midwestern gardens each summer.
Provide your hydrangea shrubs with a partial-sun and partial-shade exposure, with more shade in regions with hot summers. Some shade is desired but full, deep shade will inhibit bloom performance, so partial daily shade or filtered shade is preferable.
Water your hydrangea deeply to keep the root zone evenly moist at all times, but not sopping wet. During the heat of summer, periods of drought or when growing in a sunny exposure, more frequent watering will be needed to keep the flower heads from drooping and the leaf tips from scorching.
Prune away all dead plant tissues and roughly 1/3 of the oldest branches each year in the summer or fall after bloom to stimulate bushy growth and bloom. Re-size or re-shape the hydrangea by pruning all of the the branch tips immediately after flowering in the late summer. In cold climates simply prune away the dead branches killed by the winter cold in the early spring, before new green growth emerges.
Protect your hydrangea branches and flower buds from late-season cold snaps by draping the shrubs when heavy frost or freezing temperatures are anticipated. Lightweight frost -protecting tarps from the nursery or household sheeting should be laid down in the early evening and removed in the morning once the sun is fully up and temperatures have warmed.
Fertilize your hydrangea shrubs once or twice a year with a complete, slow-release fertilizer with a guaranteed analysis of 10-10-10 or 5-10-10. Make the first application in the spring after the last hard frost has passed and the soil has thawed. Make the second in early to mid-summer. Follow the product dosing directions for the size of the planting area but do not exceed 2 pounds of fertilizer for every 100 square feet. Water in well until the soil is drenched to a depth of at least a foot.