How to Grow Hydrangeas: A Complete Guide to Soil, Light, Watering and Pruning

The hydrangea is a deciduous shrub of the genus Hydrangea, also known as the bigleaf hydrangea or zi yang hua. Its many small flowers cluster densely into large spherical flower heads, commonly in blue, pink, purple and white, and it usually blooms in late spring and early summer. It is a very popular ornamental flower for courtyards and balconies.

When growing hydrangeas, soil and light are the foundation. It likes loose, fertile, slightly acidic soil with good drainage, which can be made by mixing garden soil with leaf mold and river sand. The flower color also changes with the soil's pH: acidic soil tends toward blue, alkaline soil toward pink. It likes a semi-shaded environment and is suited to a spot with diffused light; in summer, avoid the strong midday sun so the leaves do not get scorched.

Hydrangeas have large leaves and a high water demand, so keep the potting soil moist during the growing season. Water promptly once the surface soil dries out. In high temperatures you can also spray water on the leaves and the surrounding area to cool things down, but be careful not to let water accumulate, which can cause root rot. Before and after flowering, you can supplement with phosphorus and potassium fertilizer; during the peak growing season, just apply light fertilizer frequently.

Pruning is also crucial. Most varieties differentiate their flower buds on old wood, so it is generally best to prune after flowering, cutting off spent blooms and overly dense or thin, weak branches. Do not prune heavily in autumn or winter, or you may cut off next year's flower buds. A few varieties that bloom on new wood can be handled with some flexibility.

As for common problems, wilting leaves are usually caused by lack of water or too much sun, and the plant will recover with timely shading and watering; if it grows only leaves and no flowers, this is often related to insufficient light, too much nitrogen fertilizer or poorly timed pruning. Master these key points of soil, water, fertilizer and pruning, and your hydrangea will produce full flower balls year after year.