When to plant Hollyhock in Cool Australia

Cool zone — applies to Hobart, Canberra, Ballarat, Orange, Armidale and similar areas. Growing elsewhere? Temperate · Subtropical · Tropical · Arid.

Raise hollyhock seedlings from January to April, then transplant them out, giving this hardy biennial the cool season to establish before it towers into flower. Sow the seed about 8 mm deep; germination is fairly quick and even at 6–20 days. Grow the seedlings on and space them 30–50 cm apart with rows 45–60 cm apart, allowing the tall spires room to stand. Hollyhocks take a long 200–220 days to reach flowering, so autumn-sown plants overwinter as rosettes and send up their stately, saucer-flowered stems the following summer across cool gardens around Hobart, Canberra and Orange.

Sowing calendar — cool zone

Green months are your sowing window: January to April.

Growing notes

Hollyhocks love the reliable winter chill of cool zones like Ballarat and Armidale, overwintering as leafy rosettes and rising to two metres or more in their second season. Start seedlings in punnets or pots from late summer to autumn, then transplant into a warm, sunny, sheltered spot with rich, free-draining soil once they are sturdy.

The defining failure mode is rust. Hollyhock rust shows as orange-brown pustules on the undersides of leaves and can defoliate a plant in a damp cool-zone spring. Space plants at the full 30–50 cm for air flow, water at the base rather than over the leaves, remove and bin affected foliage promptly, and clear all old growth at the end of the season so spores do not carry over. Choosing a sunny, breezy position does more to prevent rust than any spray.

Being so tall, hollyhocks catch the wind, so plant against a fence or wall and stake the spikes as they extend. They are short-lived but self-sow readily, so leave a few pods to shed seed and you will rarely need to resow. Deadheading the main spike can coax a second, shorter flush lower down before the plant tires.

Hollyhock at a glance

Common questions

When should I start hollyhock seed in a cool climate?

Raise seedlings from January to April and transplant them out to establish over autumn and winter. They then flower the following summer after a long 200–220 day lead.

What are the orange spots on my hollyhock leaves?

That is hollyhock rust, a fungal disease common in damp springs. Remove affected leaves, water at the base, space plants for air flow, and clear old growth each season.

Do hollyhocks come back every year?

They are biennials that flower in their second year, but they self-sow so freely that a patch usually renews itself. Leave a few seed pods to drop for next season's plants.

How do I stop tall hollyhocks blowing over?

Plant them against a fence or wall in a sheltered spot and stake the spikes as they grow. Their height makes them very vulnerable to wind in exposed cool gardens.

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