HARDINESS: Zones 4 to 8
PREFERRED SOIL pH: Acid
PREFERRED SOIL TYPE: Fertile, moist
PREFERRED LIGHT: Partial shade
ATTRIBUTES: Deep green foliage and deep green lacy while flower clusters; for walls, buildings, frees
SEASON OF INTEREST: Year-round
TYPE OF VINE: Deciduous woody perennial; climbs by clinging with aerial rootlets
FAVORITES: H. petiolaris
QUIRKS: May not bloom for several seasons after planting; needs early training
GOOD NEIGHBORS: Rhododendron, azalea, perennial geranium, iris, ornamental grasses
WHERE IT GROWS BEST: Partial shade in acid soil high in organic matter
POTENTIAL PROBLEMS: Yellowing leaves when grown in alkaline soil
RENEWING PLANTS: Vines live many years without rejuvenation
CRITTER RESISTANCE: Excellent
SOURCE: Bedding plants
DIMENSIONS: Up to 65 ft (19.8 m) long
Climbing Hydrangea in the Landscape
Gardeners with shady spots are fortunate, because they can grow climbing hydrangea, one of the loveliest and most care-free vines. This plant grows from shaggy-barked, woody stems clothed from spring to fall in glossy, dark green, heart-shaped leaves that turn a glowing golden yellow in fall. In summer, 8 in (20.3 cm) wide clusters of snowflake-shaped white flowers persist for several weeks.
Strong aerial rootlets help climbing hydrangea attach itself to trees, walls, or buildings. The rootlets will
not harm masonry, but make sure there are no existing cracks where roots can invade. Because the thick vines and foliage retain moisture and can cause wooden walls to rot. put up a sturdy trellis 1 ft (0.3 m) or more from a wooden wall to allow air to circulate behind the vine. And select a permanent site with plenty of room, as climbing hydrangea reaches a mature height of 65 ft (19.8 m).
Growing Climbing Hydrangea
Easy to plant and care for, climbing hydrangea will repay a good start. A site in full sun is acceptable in cool-summer climates, if the soil is moist. Partial shade is better in hot areas. This vine is a natural for a woodland garden where leaf litter creates a slightly acid soil pH. Alkaline soil causes leaves to yellow and keeps the vine from thriving. If your soil is alkaline, add garden sulfur according to the package label to create a slightly acidic soil pH before planting; test the soil annually and reapply as needed. Prepare a hole in spring, making it as deep as the vine's nursery container and twice as wide. Add a balanced, controlled-release fertilizer at the rate suggested on the package. Set the plant in, fill around it with soil, and water.
You'll need to help vines climb for the first year or two, until the aerial roots grab the support. For a masonry surface, pound in "rose nails," which have a soft metal head that you can bend around a stem to hold it to the support. Tie the stems to a trellis with soft twine. Water as needed to keep the soil moist during the growing season and apply a 3 in (7.6 cm) thick mulch of organic matter, such as chopped oak leaves, to retain moisture. This thick-leaved vine is virtually untroubled by either pests or diseases. Climbing hydrangea needs little pruning other than to control its height and spread. Prune awkward outward-growing shoots or damaged vines at any time.
Increasing the Bounty
Climbing hydrangea is easy to propagate from cuttings. Early in the growing season, take 6 in (15.2 cm) long tip cuttings from unwanted branches that are not attached to a support. Remove leaves from the bottom half of the cuttings and insert each halfway into moist sand or a well-drained potting soil. Keep the soil moist and set the cuttings in a shady site. Move the pots into a cold frame or to a room that remains above freezing through the winter. The following spring, plant the cuttings outdoors where they are to grow.