Climbing hydrangea is a perennial deciduous vine native to moist, fertile woodland areas around the world. It will climb up almost any structure, including brick, stucco, stone, chimneys, arbors and even trees. Small white, fragrant flowers are borne in spring and summer, and foliage sometimes takes a rich, yellow color before dropping in the late fall. Climbing hydrangea plants are slow to become established in the garden, but once they reach maturity, they can grow quickly and become invasive if not cared for properly.
Select a planting location with well-drained, fertile soil near a wall or trellis for the plant to climb. Choose partial shade in warmer climates and full sun in cooler climates. Prepare the planting area by incorporating 1 to 2 inches of organic compost into the soil using a garden tiller. Climbing hydrangea prefers rich soil high in organic matter.
Plant climbing hydrangea in early spring after all threat of frost has passed. Dig a hole as deep as the container in which the plant was previously grown and about three times its width. Set the plant in the hole so the crown, or the area where the roots meet the stem, is at ground level. Cover with soil and pack the earth down around the roots.
Tie the climbing hydrangea plant to the structure it will climb using soft twine. Place a wooden or metal stake in the ground behind the plant to provide support if it is planted near a wall, and then tie the plant to the stake. If planted near a trellis or tree, simply tie the plant to the structure. This will help support the plant as it grows.
Water climbing hydrangea plants deeply and slowly immediately after planting. Continue watering deeply once per week during the summer months, anytime the soil is dry. Water once every two weeks in spring and fall by pouring two to three 5-gallon buckets of water around the base of the plant. Do not water in winter.
Feed climbing hydrangea in spring during the first two years of growth. Use a balanced, slow-release organic fertilizer according to the manufacturer's instructions. As a general rule, use about 1 tbsp. of fertilizer per each foot of the plant's height. Fertilize once in spring and once in fall starting in the third year of growth.
Spread a 3-inch layer of mulch over the soil surrounding climbing hydrangea plants in spring. Begin the mulch layer about 3 inches from the base of each plant to allow room for growth. Replenish the mulch anytime it begins to deteriorate. Use bark mulch, hay or grass clippings for the best results.
Prune climbing hydrangea plants after flowering in late summer or early fall. Remove spent flowers and trim back stems and leaves with pruning shears until the desired height and spread is reached. Although slow-growing, it may need to be controlled once mature, particularly if you don't want the plant to spread to other areas of the garden.