Climate matters. This page is a practical baseline. Confirm cultivar, local frost/heat conditions, mature size and regional restrictions before planting.
Hollyhock — Growing reference
| Scientific name | Alcea rosea |
|---|---|
| Seed germination (days) | 10–14 |
| Soil temperature for germination (°C) | 15.6–21.1 |
| First harvest or flowering (days) | 365–730 |
| Measured from | Seed |
| Plant spacing (cm) | 45.7–61 |
| Mature height (cm) | 121.9–243.8 |
| Mature spread (cm) | 45.7–61 |
| USDA hardiness zones | 3–9 |
| Light | Full sun |
| Water | Moderate |
| Sowing method | Direct sow |
Growing directions
Sow seeds 1/4 in deep; hollyhocks are biennial or short-lived perennials that flower the second year from seed and self-sow freely to maintain the planting. Rust fungus is the most common disease — look for orange pustules on leaf undersides and remove affected foliage promptly, avoiding overhead watering. Plant against walls or fences and provide loose staking for the tall, top-heavy flowering spikes. Allow some seed to mature and fall to keep the colony self-renewing.
Source and local conditions
Typical planning ranges from OpenPlantDB (CC0). Cultivar, climate, season and growing method can change these values. Confirm the seed label and local guidance before planting.
Source & verification
OpenPlantDB · CC0