Climbing hydrangeas are flowering deciduous vines. These plants are true climbers, using the holdfasts (suckers) on their branches to scale walls and other structures. These large plants sometimes reaching 50 feet tall or more at maturity. In early summer, they produce fragrant, lacy ("lace-cap"), flat-topped, white flower heads. These lace caps can be 5 inches or more in width and are composed of showy flowers on the outside and less-than-showy flowers on the inside. When they dry out, the flower heads turn reddish brown. Some gardeners cut off the dried flower heads for use in crafts. The leaves are a medium-green color during the summer and turn yellowish in autumn. But these plants are not grown for their fall-foliage color. The plants' peeling bark provides some winter interest.
- Botanical Name: Hydrangea anomala ssp. petiolaris
- Common Name: Climbing hydrangea
- Plant Type: Deciduous vine
- Mature Size: 50 feet tall
- Sun Exposure: Partial shade
- Soil Type: Moist
- Soil pH: Acidic
- Bloom Time: Spring, Summer
- Flower Color: White, blue, pink, purple
- Hardiness Zones: 4 through 7
- Native Area: Asia
How to Grow Climbing Hydrangeas
You can grow climbing hydrangea vines to climb up trees, garden arbors, trellises, pergolas, or fences. Because the vines become so large and heavy over time, be sure that the host structure can support the weight of the vines. The plants can also be pruned and maintained in shrub form. The vines commonly don't bloom until they are three to five years old.
Climbing hydrangea can also be used as ground covers, and they will take root where their suckers make contact with the ground. This helps the plant to spread and fill in an area, cutting down on weed growth. Some gardeners make use of the plant's white flowers in moon gardens. And because they are also salt-tolerant plants, climbing hydrangea is popular in seaside communities. The plants' peeling bark provides some winter interest.
Relatively few hardy flowering vines tolerate shade, but climbing hydrangea is one of them. In fact, in hot climates, they actually prefer a location with at least partial shade. Elsewhere, they typically will do alright in more sunny areas, if adequately watered. Climbing hydrangeas that do get more sun tend to bloom better.
Plant climbing hydrangea in soil that drains well and contains plenty of compost. Aim for a soil pH that is slightly acidic, and keep the soil evenly moist. Apply a 3-inch layer of mulch to help retain water in the ground around the root zone.
As with other hydrangea plants, this species likes constantly moist soil. You should place it where it will get watered about 1 inch weekly, or even more often in hot weather. The Greek root hydr- in the name, hydrangea refers to water, and angeon comes from the Greek for "vessel."
Temperature and Humidity
This plant does well in temperate climates but it doesn't like hot, humid conditions. It can be damaged by sunburn and prefers daytime temperatrures around 70 F and night temperatures around 60 F. It will set buds only if there are six weeks of temperatures below 65 F. A sudden frost can damage the buds and you may not see flowers the next year.
Fertilize this plant in the spring before the leaves begin to bud. Granular fertilizer with a high phosphorous count will create beautiful blooms on your hydrangeas. You can also fertilize again after the flowers have bloomed in the summer.
Newly planted climbing hydrangea vines are slow to grow and slow to bloom. But there is not much you can do about it other than to start out with the largest plants possible (of course, you will pay extra at the garden center for larger plants).
Once the plants are established, climbing hydrangea tend to be vigorous growers and may need pruning in summer to keep them under control, if desired.
Concerns About Climbing Hydrangea on Walls
There is some debate as to whether owners of brick homes should allow climbing hydrangeas to climb up their walls (or brick chimneys). The most widely held opinion seems to be that they are safe for brick surfaces as long as the brick's mortar is in good shape. They vines attach with a sticky substance and do not grow into the mortar or cracks between bricks. This sticky stuff can be hard to clean off if you want to remove the vine.
Once a mature vine has covered a brick surface, cracks can always develop in the mortar, and the vines may hide the damage or make access difficult for repairs. For surfaces like shingles, siding, and clapboards there is concern that the weight of the vines might loosen them, and you won't be able to paint the surface without removing the vines. More generally, the problem with growing vines up a house wall is that it will eventually get into areas where you do not want it, such as gutters. Pruning can control this, but this can be difficult on a multistory home.