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Hydrangea anomala ssp. petiolaris
Climbing Hydrangea
Japan, Korea, Russian Far East (Sakhalin); moist deciduous and coniferous forests
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Overview
Hydrangea anomala ssp. petiolaris is a self-clinging deciduous climbing shrub reaching 30–50 feet (9–15 m) tall with a spread of 6–10 feet (1.8–3 m). The plant attaches to surfaces using aerial rootlets (adventitious roots) that grip masonry, stone, and rough-barked tree trunks without additional support. Dark green glossy leaves are heart-shaped, 2–4 inches (5–10 cm) long, with serrated margins and yellow fall color. Flat-topped lacecap corymbs 6–10 inches (15–25 cm) across appear in June, composed of an outer ring of sterile white ray florets surrounding a center of small creamy-white fertile florets. Bloom duration is 3–4 weeks. The flowers carry a light fragrance and are visited by bees and other pollinators. Spent flower heads persist through winter, and on mature plants the bark exfoliates in cinnamon-brown strips. Establishment is slow — plants commonly produce minimal growth for the first 2–3 years before climbing accelerates. Aerial rootlets can damage wood siding, painted surfaces, and mortar joints on aging masonry. Blooms develop on old wood, and late-spring frosts can reduce flower production. All parts of Hydrangea contain cyanogenic glycosides and are toxic to pets and humans if ingested in quantity. Hardy to USDA zone 4.
Native Range
Native to Japan, Korea, and the Russian Far East including Sakhalin Island. Grows in moist deciduous and coniferous forests, climbing tree trunks at low to mid elevations.Suggested Uses
Trained on masonry walls, stone fences, large tree trunks, and pergolas in zones 4–9. The self-clinging habit covers vertical surfaces without trellis or wire support, though aerial rootlets damage wood siding, painted surfaces, and aging mortar joints. The 2–3 year establishment period limits use where rapid coverage is required.How to Identify
Appearance
Size & Dimensions
Height30' - 50'
Width/Spread6' - 10'
Reaches mature size in approximately 7 years
Bloom Information
Flat-topped lacecap corymbs 6–10 inches (15–25 cm) across open in June across most of the range, with bloom shifted to late May in zones 8–9 and to early July in zone 4. Individual flowers persist 3–4 weeks. Flowers form on old wood, so late-spring frosts in zones 4–5 can reduce or eliminate flowering for that season. Spent flower heads dry to tan and remain on the plant through winter.Detailed Descriptions
Flower Description
White lacecap corymbs 6-10 inches (15-25 cm); sterile white ray florets surrounding creamy-white fertile centerFoliage Description
Dark green, glossy, heart-shaped, serrated, 2-4 inches (5-10 cm); yellow fall colorGrowing Conditions
Sun Requirements
Requires 2-5 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in partial to full shade in moist, humus-rich, well-drained, acidic to neutral soil with pH 5.5–7.0. Tolerates full shade, though flowering is more abundant where plants receive 2–3 hours of morning sun. Establishment is slow — climbing growth often begins only after 2–3 years in place. First-season watering is weekly in the absence of rain; established plants tolerate brief dry periods but lose foliage and reduce flowering during prolonged drought. Aerial rootlets damage wood siding, painted surfaces, and aging mortar joints. Hardy to USDA zone 4 with foliage tolerance to −30°F (−34°C).Pruning
Pruning is performed after flowering in July, since blooms form on old wood. Wayward branches are removed and congested growth is thinned. Established plants tolerate hard renovation pruning but lose 1–2 seasons of flowering as a result. Pruning in fall or winter removes the following year's flower buds.Pruning Schedule
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