Hydrangeas grow in both large and small varieties, with blue, pink or white flowers and bright green foliage. The bushes grow well from U.S. Department of Agriculture growing zones 3 to 10 in some cultivars, and they live for many years. All hydrangeas require specific lighting, moisture and soil to thrive, including the right plant food and fertiliser.
Site and Season
Plant new hydrangeas in the right site and season for long-term success. Put the bushes in the ground in mid-spring, when the ground warms but before summer heat arrives. Find spots with indirect or partial light to avoid burning or drying. Hydrangeas do best in morning sun and afternoon shade, and they fail in deep shade. Put the plants only in sites that drain quickly, as they fail in standing water or mud.
Give hydrangeas a rich, nutritious start with the right soil amendments. Turn 3 to 4 inches of organic compost into the top 10 to 12 inches of soil in any planting site to loosen and nourish the soil. Add more compost as necessary to build a loose, dark and crumbly foundation. Hydrangeas cannot grow in tight soil and don't garner enough nutrition from pale, sandy soil.
Fertiliser and Feedings
Wake established hydrangeas in early spring with compost applications to keep the soil moist, nutritious and quick-draining. Mix 3 inches of organic compost into the top 3 inches of soil in a 12-inch circle around each plant. Give the hydrangeas balanced 8-8-8 or 10-10-10 granular fertiliser in March, May and July to keep the plants growing and blooming. Sprinkle the fertiliser onto the soil in your 12-inch circle, then dig it into the top 3 inches of soil and water. Follow manufacturer directions in regard to quantity.
Water and Mulch
Hydrangeas cannot live on soil and fertiliser alone. These are thirsty plants and suffer in hot or dry soil. Give each plant 4 to 5 inches of water every week and monitor the soil and foliage for drying. Put 2 inches of organic mulch on the soil in an 18-inch circle around each hydrangea. The mulch keeps soil moist and free of weeds and adds more nutrition to the foundation as it breaks down. Replenish this layer regularly.