Hollyhock Growing Guide

Alcea rosea, Alcea ficifolia

Crop Rotation Group

Miscellaneous ●

Soil

Fertile, well-drained soil enriched with compost.

Position

Full sun to partial shade.

Frost tolerant

Yes, hollyhocks are hardy biennials or short-lived perennials. Plants are hardy to about -18°C (0°F). New seedlings that come up in spring easily survive late freezes.

Feeding

Mulch over the plants’ root zones with rich compost just as new growth emerges in spring. Drench plants with a liquid fertiliser when they begin to grow tall, and again three weeks later. Regular feeding will extend the bloom time of hollyhocks.

Spacing

Single Plants: 30cm (11") each way (minimum)
Rows: 30cm (11") with 30cm (11") row gap (minimum)

Sow and Plant

The easiest way to get a start with this reseeding biennial is to sow seeds where you want the plants to grow in early spring or late summer. Young hollyhocks can be transplanted, but they often grow best from seed. Depending on climate and hollyhock variety, plants may be annual, biennial or perennial. The natural life cycle of hollyhock is to sprout in late summer, grow into a winter-hardy green rosette, and bloom the following summer. Plants started in early spring may bloom their first year. Young plants need water when they are actively growing. A surface mulch suppresses weeds while making the plants look more attractive.
Our Garden Planner can produce a personalised calendar of when to sow, plant and harvest for your area.

Notes

Hollyhocks grow to 1.8 m (6 feet) tall, so plan to stake them if you live in a windy area. Single-flowered varieties are more weather resilient that doubles because single blossoms shed rain. When well pleased with their site, hollyhocks reseed for many years, with new seedlings appearing in autumn and spring. Comparatively compact French hollyhocks are easy to grow as reseeding annuals. They are the best hollyhocks for containers.

Harvesting

Gather stems for use in cut arrangements as you need them, when at least half of the flowers on a stem are open. Cutting old blossoms will stimulate modest reblooming. Allow a few spikes to stay on the plants until they shed mature seeds.

Planting and Harvesting Calendar

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Pests which Affect Hollyhock

Aphids (General)

Slug

Snail