Hollyhock Alcea rosea
Hollyhock (Alcea rosea) is a biennial flowering plant in the Malvaceae family. It grows 1.5–2.5 m (4.9–8.2 ft) tall and 40–70 cm (16–28 in) wide, wants full sun and moderate water, and is hardy to about -25 °C (-13 °F). Space plants about 60 cm (24 in) apart.
Plan Hollyhock in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Hollyhock at a glance
| Type | Biennial flowering plant |
|---|---|
| Family | Malvaceae |
| Mature height | 1.5–2.5 m (4.9–8.2 ft) |
| Mature spread | 40–70 cm (16–28 in) |
| Spacing | 60 cm (24 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance none |
| Cold hardiness | About -25 °C (-13 °F) once established (roughly USDA zone 5) |
| Heat stress | Likely above about 33 °C (91 °F) |
| Flowering | about 52–64 weeks after planting, for 9–13 weeks |
| Days to maturity | About 365 days from planting |
| Wind tolerance | None |
| Pollinator value | High |
| Edible | Yes: flowers, young leaves |
| Common in gardens of | 🇬🇧 United Kingdom, 🇺🇸 United States, 🇫🇷 France, 🇩🇪 Germany, 🇨🇳 China |
Is Hollyhock toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Hollyhock is not known to be toxic to people or pets.
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 Hollyhock
No well-documented helpful pairing. Group it with plants that like full sun and moderate water.
See Hollyhock in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- Brooklyn Botanic Garden (4 plants)
- Monet’s gardens at Giverny (70 plants)
- Riverside botanical garden (13 plants)
Questions about Hollyhock
- How far apart should I plant Hollyhock?
- About 60 cm (24 in) apart, centre to centre. A mature plant spreads 40–70 cm (16–28 in).
- Does Hollyhock need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Hollyhock need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is Hollyhock?
- It tolerates about -25 °C (-13 °F) once established, roughly USDA zone 5. As a biennial it is usually planted out after the last frost and flowers in its second year.
- When does Hollyhock flower?
- About 52–64 weeks after planting, for 9–13 weeks.
- Is Hollyhock poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Hollyhock is not known to be toxic to people or pets.
- What grows well with Hollyhock?
- There is no well-documented companion pairing for Hollyhock. Group it with plants that like the same sun (full sun) and water (moderate).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
- FAO Irrigation and Drainage Paper 56 — Crop Evapotranspiration, FAO
- RHS Plant Finder, Royal Horticultural Society
- University extension gardening guides (general), Various land-grant university extensions
Notes and assumptions
- Typical garden-cultivar values; varieties differ.
- Prone to rust; tall stems may need staking.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
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- Tropical hibiscus Hibiscus rosa-sinensis
- Rose of Sharon Hibiscus syriacus
- Small-leaved lime (linden) Tilia cordata
- Cacao Theobroma cacao
- Durian Durio zibethinus
- Red silk-cotton tree (kapok) Bombax ceiba
- African baobab Adansonia digitata