Hydrangea petiolaris

Soil: Average, medium moisture, well-drained soils. Mulch plants after soil has warmed to conserve moisture and buffer soil temperatures.
Light: Most varieties tolerate full sun in the North, but benefit from afternoon shade. Tolerates full sun only if grown with consistent moisture. In the South, plants require afternoon shade. Intolerant of drought, with foliage tending to decline considerably in dry conditions
Water: Water to keep soil moist, but not wet.
Spacing: 5 - 10 ft.
Fertilizing: Fertilize once in spring with a fertilizer designed to encourage blooms (such as 15-30-15).
Winterizing: Remove and destroy any fallen foliage that was infected by powdery mildew. If desired, wrap with burlap or other material to help flower buds overwinter in colder climates.
Maintenance & pruning: This variety blooms on old wood. If it is growing too large, prune to the desired size by August (to be safe). Later pruning will damage developing flower buds. In spring, only prune out dead wood once the new growth has emerged. Young plants may be transplanted when dormant in early spring.