Updated: Nov 2, 2021
"And now for something completely different" as the cast from Monty Python's Flying Circus repeatedly pronounced as their comedy sketches would shift directions, Hydrangea anomala ssp. petiolaris is unlike all other hydrangeas. Most commonly, we might think of Hydrangea macrophylla, the shrubby form with pink, white, or blue pompoms famously planted in masses along San Francisco's Lombard Street. The subject of this post, however, is a vine, known as climbing hydrangea.
Visually, there are similarities between the two. Climbing hydrangea has leaves with similar shapes but are smaller than its bigleaf counterpart. The separate sterile and fertile flowers combine in one white flattop cluster not unlike lacecap hydrangeas. People will understand this species as a hydrangea but perplexed by its form, clinging to walls and trees if allowed. On trees, climbing hydrangea might reach sixty plus feet or on walls spread similar widths. How? With assistance from aerial roots along the stems, just as ivy will cling to their support structures.
With so much interest in green walls, we should not miss the advantages of planting vines. In this case, one vine can replace countless wall-mounted plants in their restricted planting space, lessening maintenance and watering needs. However, climbing hydrangeas are deciduous, missing an opportunity to capture winter rainwater. Perhaps a solution is to combine, creating a tapestry of color and textures, allowing vines to infill as they grow while evergreens collect rain.
There are challenges to using H. anomala ssp. petiolaris. As with most plants in the species, hydrangeas like water, and in California, may be too much of a challenge where water is becoming more scarce. Several references discuss its drought tolerance, but I would like to see more context before I commit to such claim. It also prefers shade, so north facing walls, maybe east facing if protected from late morning sun, are its best exposures. This location creates an opportunity where ground roots could crawl deep underground at a structure's foundation where soil will be cool and hopefully retain more moisture, so I am not fully dismissing its use. If there are any thriving in California, I would love to know.
Cornell School of Integrative Plant Science
Botanical Name: Hydrangea anomala ssp. petiolaris
Hydrangea: Greek, hydor, for water; angeion for small vessel, as in the urn-shaped fruit.
Anomala: Referring to not being the norm within the genus
Petiolaris: Having a large leaf stalk
Common Name: Climbing hydrangea
Family Name: Hydrangeaceae
Origin: Russia, Korea, Japan
Positioning: Vertical, background
Garden Themes: Cottage, children’s, cutting, shade, woodland
Uses: Specimen, climber, rock/brick/concrete walls, vertical mass, screen/privacy
Type: Deciduous vine
Form: Upright, spreading, pending intent on support structure
Size: Up to 60' tall and variable widths
Outstanding Feature(s): Flower, form
Stem: Striking exfoliating bark, red-brown with minute aerial roots
Color: Dark green, turning golden yellow in Autumn
Surface: Glabrous, glossy
Flower: Spring to Summer. Flat corymbs of both sterile and fertile white flowers
Fruit: Autumn. Urn-shaped capsule, each containing one seed
cultural requirements, tolerances & problems
Sunset Zones: A2, A3; 2-21
USDA Zones: 4-8
Light: Light to deep shade
WUCOLS SF Bay Area Hydro Zone: Moderate
Texture: Sand, loam, clay, well composted
Moisture Retention: Well-drained with consistent light moisture
pH: Acidic to neutral
Tolerances: Heavy shade
Problems: Low toxicity
Branch Strength: N/A
Insects: None observed at time of posting
Disease: None observed at time of posting
citations & attributions
Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.
Breen, P. "Hydrangea anomala var. petiolaris." Oregon State University, College of Agricultural Services, Department of Horticulture, Corvalis. Accessed on October 5, 2021, from https://landscapeplants.oregonstate.edu/plants/hydrangea-anomala-var-petiolaris.
Extension Gardener. "Hydrangea anomala." North Carolina State University, Raleigh. Accessed on October 5, 2021, from https://plants.ces.ncsu.edu/plants/hydrangea-anomala/.
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
Plant Finder. "Hydrangea anomala subsp. petiolaris." Missouri Botanical Garden, St. Louis. Accessed on October 5, 2021, from https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=d370.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on June 28, 2021.
On tree: "Climbing Hydrangea Vines" by beautifulcataya is licensed under Creative Commons NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0).