If you love the beauty of a traditional hydrangea bush and are looking to add visual interest to walls or structures in your landscape, climbing hydrangeas may be for you. Native to Asia, crawling hydrangeas are flowering deciduous vines best planting in late spring. These plants are true climbers, using the holdfasts (suckers) on their branches to scale walls and other structures.
Climbing hydrangea plants grow very slowly, and may take as many as three to five years just to reach the flowering stage. That being said, once established, they are truly eye-catching—they can sometimes reaching 50 feet or more at maturity, and produce fragrant, lacy white flower heads at the beginning of each summer. These lace caps can be five 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 on climbing hydrangea plants turn reddish-brown, and the bark begins to peel. Some gardeners cut off the dried flower heads for use in crafts, while many others allow the plants to die back on the vine.
|Botanical Name||Hydrangea anomala ssp. petiolaris|
|Common Name||Climbing hydrangea|
|Mature Size||30–50 ft. tall, 5–6 ft. wide|
|Sun Exposure||Partial shade, full shade|
|Soil Type||Moist but well-drained|
|Bloom Time||Late spring, summer|
|Hardiness Zones||4–8 (USDA)|
|Toxicity||Toxic to dogs and cats|
Climbing Hydrangea Care
Climbing hydrangea vines are eye-catching blooms, often trained to grow up trees, garden arbors, trellises, pergolas, and fences. Because the vines can become so large and heavy, it's important to make sure that the host structure can support the weight of the vines.
While they're often seen as vines, climbing hydrangeas can also be pruned and maintained in shrub form, or used as ground covers, where they will take root where their suckers make contact with the ground. Not only does it make for a beautiful scene, but it will also cut down on weed growth.
Once a mature vine has covered a surface, cracks can always develop, and the vines may hide the damage or make access difficult for repairs. For surfaces like shingles, siding, and clapboards there is a 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 it can be difficult on a multistory home.
Relatively few 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 (and sometimes even full) shade. Elsewhere, they typically will do alright in more sunny areas, if they're consistently and adequately watered. An important thing to keep in mind: Climbing hydrangeas that get more sun will bloom more vibrantly and fully than those that experience too much shade.
Plant your climbing hydrangea vine in soil that drains well and contains plenty of nutrient-dense compost. Though the climbing hydrangea isn't super particular about its soil pH level, it will grow and bloom best in a mixture that is slightly acidic in nature. In order to help maintain moisture in the soil (without it getting waterlogged), apply a 3-inch layer of mulch around the root zone to help retain water.
Similar to other hydrangea plants, climbing hydrangeas like constantly moist soil—in fact, the Greek root hydr- in the name refers to water, while angeon comes from the Greek word for "vessel." They need to receive at least one inch of water weekly (via either rain or traditional watering methods), and can sometimes necessitate more if the weather is especially hot or dry.
Temperature and Humidity
Climbing hydrangea plants do well in temperate climates but it doesn't like hot, humid conditions. It can be damaged easily by sunburn and prefers daytime temperatures that hover around 70 degrees Fahrenheit and night temperatures around 60 degrees Fahrenheit. Furthermore, climbing hydrangea vines will only set buds if they experience at least six weeks of temperatures below 65 degrees Fahrenheit. Additionally, a sudden frost can damage the buds, and you may not see flowers the next year.
Fertilize your climbing hydrangea vine each spring before the leaves begin to bud—granular fertilizer with a high phosphorous count will help create beautiful blooms. You can also fertilize again after the flowers have bloomed in the summer, though it's not a must.
Is Climbing Hydrangea Toxic?
Several parts of the climbing hydrangea plant (and all hydrangea plants) are poisonous, including the buds, flowers, and leaves. They all include a compound called glycoside amygdalin, which can transform into cyanide. While your pet will need to ingest large amounts of the plant for it to truly be deadly, it's a good idea to keep an eye on them regardless. If you notice your pet exhibiting any of the below symptoms, contact your vet or emergency services immediately.
Symptoms of Poisoning
- Abdominal pain
- Difficulty breathing
Pruning Climbing Hydrangea
Newly planted climbing hydrangea vines are slow to grow and slow to bloom. There 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 tends to be vigorous growers and may need pruning in summer to keep them under control, if desired.
Common Pests and Diseases
The issues climbing hydrangeas face with pests and diseases are very similar to those of traditional hydrangeas. Because of the density of the foliage and blooms, climbing hydrangea can often become afflicted with mildew and leaf spot. Beyond that, you may spot signs of spider mites, scale, and aphids, all of which can be treated with a mild insecticide or neem oil.