How to Fertilize Hydrangeas

Hydrangeas are a Japanese native flowering plant that thrive, according the USDA, in cold hardy areas. There are 23 different species of Hydrangea, only five are actively cultivated in the United States.

The most common of the species, Hydrangea macrophylla, has broad leaves with light blue blooms. The H. macrophylla var. normalis, or Lacecap, has a inner circle of tiny white flowers with an outer circle of light purple flowers. These species do well in zones as far north as Zone 6.

Instructions

1. Choosing a fertilizer is the first step to healthy hydrangeas. The type of fertilizer can range from organic additions to the soil, such as manure and compost, to chemical fertilizers. If you opt for a chemical fertilizer, most professional gardeners recommend using a slow release once or twice a year. A less expensive fertilizer such as a 10-10-10 will do the job just as well if it is applied twice during the summer.

2. The time to fertilize your hydrangeas depends on the area where you live. Gardeners in in Zone 6 should fertilize in early spring, usually in mid April, and then again in June or July. Those in the most southern states where the summers are longer can fertilize as early as March and as late as August.

3. Hydrangea plants that are less than 12 inches tall take one-eighth to one-quarter of a cup of fertilizer; sprinkle the fertilizer 12 inches from the base of the plants. Large hydrangeas, those that are 4 to 5 feet tall take 2 to 3 cups of fertilizer, applied along along the drip line of the plant.

Tips & Warnings

• Do not fertilize a plant that is sick or droopy. Stop fertilizing your hydrangeas in August so that they can prepare to go dormant.

References

• The United States National Arboretum
• USDA Plant Hardiness Zone Map

Resources

• Planting, Transplanting, and Fertilizing Hydrangeas