Smooth hydrangea 'Annabelle' Hydrangea arborescens
Smooth hydrangea 'Annabelle' (Hydrangea arborescens) is a deciduous perennial shrub in the Hydrangeaceae family, native to Eastern United States. It grows 1–1.5 m (3.3–4.9 ft) tall and 1.2–1.8 m (3.9–5.9 ft) wide, wants part sun to part shade and high water, and is hardy to about -34 °C (-29 °F). Space plants about 1.5 m (4.9 ft) apart.
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Smooth hydrangea 'Annabelle' at a glance
| Type | Perennial shrub, deciduous |
|---|---|
| Family | Hydrangeaceae |
| Mature height | 1–1.5 m (3.3–4.9 ft) |
| Mature spread | 1.2–1.8 m (3.9–5.9 ft) |
| Spacing | 1.5 m (4.9 ft) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance low |
| Soil pH | 5.5–7 |
| Cold hardiness | About -34 °C (-29 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Flowering | from about June for 6–11 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | None |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Eastern United States |
| Common in gardens of | 🇺🇸 United States |
Is Smooth hydrangea 'Annabelle' toxic?
- People: mildly toxic
- Cats: moderately toxic
- Dogs: moderately toxic
- Parts: leaves, buds, flowers
Cyanogenic glycosides can cause vomiting and lethargy if eaten.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Smooth hydrangea 'Annabelle'
No well-documented helpful pairing. Group it with plants that like part sun to part shade and high water.
Questions about Smooth hydrangea 'Annabelle'
- How far apart should I plant Smooth hydrangea 'Annabelle'?
- About 1.5 m (4.9 ft) apart, centre to centre. A mature plant spreads 1.2–1.8 m (3.9–5.9 ft).
- Does Smooth hydrangea 'Annabelle' need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Smooth hydrangea 'Annabelle' need?
- High water. Drought tolerance is none and waterlogging tolerance low.
- How cold-hardy is Smooth hydrangea 'Annabelle'?
- It tolerates about -34 °C (-29 °F) once established, roughly USDA zone 4.
- When does Smooth hydrangea 'Annabelle' flower?
- From about June for 6–11 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Smooth hydrangea 'Annabelle' poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs moderately toxic; for people mildly toxic. Cyanogenic glycosides can cause vomiting and lethargy if eaten.
- What grows well with Smooth hydrangea 'Annabelle'?
- There is no well-documented companion pairing for Smooth hydrangea 'Annabelle'. Group it with plants that like the same sun (part sun to part shade) and water (high).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- RHS Plant Finder, Royal Horticultural Society
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- Values reflect the 'Annabelle' cultivar group; blooms on new wood and can be cut to the ground each late winter; heavy flower heads may flop in rain.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Bigleaf hydrangea Hydrangea macrophylla
- Mock orange Philadelphus coronarius
- Panicle hydrangea Hydrangea paniculata
- Climbing hydrangea Hydrangea anomala subsp. petiolaris
- Slender deutzia (himeutsugi) Deutzia gracilis
- Mountain hydrangea (yama-ajisai) Hydrangea serrata
- Yellow wax bells (kirenga-shōma) Kirengeshoma palmata
- Rough-leaved hydrangea Hydrangea aspera