Hollyhock
Alcea rosea
Plant out around your last spring frost. Space plants 18 in (46 cm) apart.
Photo: ReetiSingh14, CC0 · source
When to plant
Timed from your frost dates, so it holds wherever you garden. Give yours and every step below becomes a date.
Optimal Transplant (Nursery Plant)
From a plantRecommended from a plant- Plant outaround your last spring frost
- First harvestabout 60 days after planting out
Optimal Late-Summer Direct Sow
From seedRecommended from seed- Sow outdoors8 weeks before your first fall frost
- First harvestabout 75 days after next spring's last frost
Optimal Indoor Start
From seed- Start indoors8 weeks before your last spring frost
- Begin hardening off1 week before your last spring frost
- Plant outaround your last spring frost
- First harvestabout 13 months after planting out
Growing hollyhock
- Spacing in the row
- 18 in (46 cm)
- Between rows
- 24 in (61 cm)
- Planting depth
- Surface-sow or cover with no more than 1/4 inch of soil; seed needs light.
- Sun
- Full Sun
- Soil
- Average to rich, well-drained soil with compost; will not tolerate wet winter soil.
- Germination
- 10-21 at 60-70°F
- Harvest season
- Summer
- Mature height
- 5-8 feet
- Support
- Stake in windy, exposed sites; the stiff spikes otherwise stand unsupported.
- Hardy to
- USDA zone 3
- Life cycle
- Biennial
Sow in place in late summer for bloom next year, barely covered; or start indoors 6-8 weeks before last frost.
Watering. Keep evenly moist; water at the base to keep leaves dry, which slows rust.
Feeding
- Growing
- Mix plenty of compost into the bed before sowing or planting.
- How often
- Once a year, in early spring. A layer of compost or a light balanced slow-release feed as new leaves appear is enough; overfeeding gives soft growth that rust attacks more easily.
- Note
- Rust is the main problem: water from below, give air space, remove infected leaves; 'Silver Puff' is listed as rust resistant.
Your hollyhock, planned to the day.
Canopy turns these timings into dates from your own frost data, places every plant at its spacing on your garden map, and tracks it all the way to harvest.