The Oakleaf hydrangea (Hydrangea quercifolia) grows up to 10 feet tall in a rounding clump style. The spread of the shrub often dramatically exceeds its height. The Oakleaf hydrangea easily spreads in one location by sending up shoots that form large colonies of shrubs. Each young stem has a unique coppery fuzz, and the green foliage has a soft fuzzy white underside. Large 12-inch-long white flowers appear in a cone shape during the summer months; as they age, they turn pink. And each fall the shrub turns a deep shade of purple, red and bronze.
Plant the Oakleaf hydrangea in lime-based soil for ideal growth. Test the soil using a pH test kit that can be purchased at any garden supply store. The soil pH test will determine if the soil is acidic or alkaline. If the planting location has acidic soil, then lime must be added at a ratio that will render the soil alkaline prior to planting.
Dig a hole in a location that offers partial shade. The Oakleaf hydrangea can often suffer wilt if it sustains direct sunlight during the height of the summer heat. Dig the hole twice the size of the Oakleaf hydrangea shrub's root ball.
Add ample organic matter to the soil at the time of planting. Use peat moss, leaf debris or aged manure. The soil should feel crumbly to the touch.
Place the Oakleaf hydrangea into the planting hole. Plant the shrub at the same soil depth as it was in its nursery container. Tamp the soil down around the shrub's root system to remove any air pockets.
Apply 2 to 3 inches of mulch, perhaps peat moss or bark chips, around the base of the Oakleaf hydrangea. The mulch will keep weed growth back, help the soil retain moisture and shade the shrub's root system during the heat of summer.
Water the Oakleaf hydrangea thoroughly. The shrub enjoys moist soil conditions. It does not withstand drought well. The shrub's flowers will die and fall to the ground during an extended drought.
Apply a general-purpose fertilizer, such as 10-10-10, every month during spring and summer. Apply 2 pounds for every 100 square feet.
Prune only old or diseased wood. The Oakleaf hydrangea blooms on the previous years wood so prune only when necessary.