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When to Plant Hollyhock Seeds: Autumn Beats Spring

Hollyhocks are biennial, so autumn-sown seed flowers the following summer while spring sowing waits a year. Surface sow — the seed needs light.

By Salma 3 min read Save to Pinterest — opens Pinterest in a new tab
Hollyhock garden wall
Photo: congerdesign, Pixabay Content License, via Pixabay
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Late summer to early autumn. Hollyhocks are biennial, so autumn-sown seed makes a rosette before winter and flowers next summer — while spring-sown seed spends the whole season as leaves and flowers a year later.

Why the timing matters

Same seed, a year apart in flowering
SownYear oneYear two
Late summer / early autumnRosette, overwintersFlowers
SpringRosette onlyFlowers

A biennial needs a full season of leaf growth before it flowers. Autumn sowing uses the tail of one year for that growth; spring sowing uses the whole of the next.

So the same packet, sown six months apart, gives flowers a full year apart.

A few modern strains are bred to flower in their first year from a very early start under cover — worth checking the packet if you want blooms this season.

Surface sow

This is the other common packet failure. Hollyhock seed needs light to germinate.

  • Press it onto the surface, or cover with the barest scattering — no more than about an eighth of an inch
  • Keep the surface moist until germination, which takes ten to fourteen days in warmth

Burying it at the depth that suits most seed simply means it does not come up.

Siting: wall, sun, space

Full sun, deep soil that drains well, and against a wall or fence.

The wall is doing real work. Hollyhocks reach six to eight feet, and unsupported spikes snap in wind just as they come into flower.

But give them space and open air on the exposed side rather than wedging them into a crowded border — which brings us to the one thing everyone who grows hollyhocks deals with.

Hollyhock rust is near-universal

Orange-brown pustules on leaf undersides, yellow spots above, caused by Puccinia malvacearum. It rarely kills a plant but disfigures it badly and weakens it over time.

What actually helps:

  • Remove and bin affected leaves — not compost, which recycles the spores
  • Clear every fallen leaf in autumn. The spores overwinter on them, and this is the single most effective step
  • Water at the base, never overhead
  • Space plants for airflow

Fungicides are available and rarely worth it in a garden. The autumn clean-up does more.

They look after themselves after that

Individual plants die after flowering — that is what biennial means. But hollyhocks self-seed freely, and seedlings fill in around the parent, so an established patch persists indefinitely.

The one thing that breaks the cycle is thorough deadheading. Leave a few seed heads to ripen and the patch perpetuates itself; remove every one and you will be sowing again.

That is why hollyhocks read as permanent cottage-garden plants despite almost none of the individual plants lasting more than two years.

Common questions

When should you plant hollyhock seeds?

Late summer to early autumn is the better window, because hollyhocks are biennial: a plant sown in autumn makes a leafy rosette before winter and flowers the following summer. Seed sown in spring usually spends that whole season as foliage and flowers the year after, so spring sowing costs you a year. The exception is a few varieties bred to flower in their first year from an early spring start under cover.

Do hollyhock seeds need light to germinate?

Yes. Hollyhock seed germinates best with light reaching it, so it should be pressed onto the surface of the compost or covered with only the barest scattering of soil, no more than about an eighth of an inch. Burying the seed is one of the commonest reasons a packet fails. Keep the surface moist until germination, which takes ten to fourteen days in warmth.

Are hollyhocks perennial or biennial?

Most are biennial, growing a rosette in their first year and flowering, setting seed and dying in the second. Some varieties are short-lived perennials that manage three or four years, and a few modern strains are grown as annuals. In practice the distinction matters less than people expect, because hollyhocks self-seed so freely that an established patch perpetuates itself and behaves like a permanent planting even though individual plants are not.

Do hollyhocks come back every year?

The patch does, though usually not the same plants. Individual biennial hollyhocks die after flowering, but they drop a great deal of seed and the seedlings fill in around them, so a clump persists indefinitely once established. Leaving a few seed heads to ripen rather than deadheading everything is what keeps that cycle going, and it is why hollyhocks are so often seen as self-sustaining cottage garden plants.

What are the orange spots on hollyhock leaves?

Hollyhock rust, caused by the fungus Puccinia malvacearum, which produces orange-brown pustules on leaf undersides and yellow spots above. It is extremely common and rarely kills the plant, but it disfigures the foliage badly and weakens it over time. Remove and bin affected leaves rather than composting them, clear all fallen foliage in autumn since the spores overwinter on it, water at the base rather than overhead, and space plants for airflow.

Where is the best place to plant hollyhocks?

Full sun, against a wall or fence, in deep soil that drains well. The wall matters for two reasons: hollyhocks reach six to eight feet and need shelter from wind that would otherwise snap the flower spikes, and a position with open air on the other side helps with rust. Give them space rather than crowding them into a border, since still humid air between plants is exactly what the rust fungus needs.

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