Hollyhock

How to recognise it

Habit

Short-lived plant: a leaf rosette in the first year, then one or more straight, usually unbranched flower spikes of 1.5–2.5 m.

Leaf

Large, round to heart-shaped, 15–30 cm, with 5–7 shallow lobes, roughly hairy and slightly wrinkled.

Flower

Saucer- to funnel-shaped, 6–10 cm across, single or double, in white, pink, red, yellow, salmon or almost black; the flowers open from the bottom upwards, from July to September.

Fruit/Seed

A flat, round disc with the seeds arranged in a ring, like a small cheese, which turns brown and dry in late summer.

Stem

Sturdy, round and hairy, somewhat woody at the base.

Roots

A long, strong taproot, which makes older plants difficult to move.

Flowering: July–September · Pruning: September–October

Why grow it?

• Single-flowered varieties are full of pollen and nectar: bumblebees and honeybees crawl deep into the flowers.
• It adds height and a romantic feel to a narrow strip along a wall or house front.
• Long flowering, from July to September, when many spring plants are over.
• It self-seeds, so you have hollyhocks year after year without replanting.
• The flowers are sometimes used as an edible garnish, and the dark flowers were once used as a natural dye.

Hollyhock: where does it grow best?

• Full sun; in partial shade it flowers less and is more prone to rust.
• Free-draining, ordinary to sandy or chalky soil; rather on the dry side than wet.
• Sheltered from wind, for example against a sunny wall or house front, so the tall stems do not blow over.
• Space around it for good air circulation: this limits rust.

Goes well with

• Catmint: Lilac clouds at the base and a magnet for bees.
• Delphinium: Blue towers beside the pink and white hollyhocks.
• Pot marigold: Orange accents at the front of the border.
• Climbing rose: Together against a sunny house front, the classic cottage garden.
• Lavender: A fragrant, drought-tolerant edging at the front.

Hollyhock: when and how to plant it?

1. Sow in May–July outdoors or in pots, 1–2 cm deep: the seedlings make a rosette this year and flower next year. No cold period is needed.
2. If you sow indoors in warmth in February–March, some varieties flower in their first year.
3. Plant young plants out in September or April, 40–60 cm apart, ideally against a sunny wall.
4. Plant them young: older plants resent being moved because of their taproot.
5. Water in dry spells during the first season; after that it is fairly drought-tolerant.
6. For tall varieties in an open spot, put in a sturdy stake straight away.

Care

Watering

Only in long dry spells, at the base and not over the leaves: wet leaves encourage rust.

Feeding

A spadeful of compost in spring. Not too much fertiliser: it gives floppy stems.

Support

In a windy spot, tie the stems to a stake or against a wall.

Lower leaves

In summer, cut off lower leaves with rust and do not put them on your own compost heap.

Letting it seed

Let a few stems finish flowering and set seed: you will have new plants next year.

Tip: Treat hollyhocks as biennials and sow a few more every year: you will always have young, vigorous plants that suffer less from rust.

Pruning and mowing

Pruning months: September–October.

When: In September–October, after flowering.

How:

• Cut faded stems back to 10–15 cm above the rosette: the plant often lives a year longer as a result.
• Leave a few stems until the seed is ripe and brown, so the plant can self-seed or you can harvest seed.
• Clear up leaves with rust, so less of the fungus overwinters.
• Lay the cut stems in a bundle in a quiet corner: small insects can overwinter in them.

Caution: If you want it to self-seed, do not cut all the stems before the seed is ripe.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Harvest the brown, dry seed discs in September, store them dry and sow in May–July. Varieties do not always come true to colour.

Self-sown seedlings

Leave seedlings where they come up, or move them while young, when they have only a few leaves.

Hollyhock: how does it get through the winter?

Hardy to −20 °C.

• The leaf rosette stays largely green in winter; the flower stems die back.
• Hardy to about −20 °C; on wet, heavy soil the rosette can rot.
• In late winter, remove old, damaged leaves from the rosette.

Diseases and pests

• Hollyhock rust: Orange-brown pustules under the leaves and yellow spots on top, from June. Remove affected leaves, do not wet the foliage, leave space and raise new seedlings every year.
• Slugs: They eat young rosettes and seedlings. Pick them off in the evening, or grow seedlings on in pots until they are sturdier.
• Falling over: Tall stems blow over. Plant against a wall or tie them to a stake.
• Small weevils: A tiny weevil lays its eggs in the flower buds and the larvae eat the seeds. Little harm to the plant; clearing away faded stems helps.

Through the year

• February: Sow indoors for flowers this year.
• April: Plant out young plants. Add compost. Watch out for slugs.
• May: Sow outdoors for flowers next year.
• June: The stems shoot up. Give support. Watch for rust.
• July: Flowering starts. Cut off lower leaves with rust.
• August: Full flower. Water in long dry spells.
• September: Flowering ends. Harvest seed, cut faded stems. Plant out young plants.
• October: Cut the last stems and clear up rusty leaves.
• December: The rosette is resting.

Did you know?

• The French name rose trémière comes from ‘rose d’outre-mer’, the rose from overseas, because it came from the East.
• The English name hollyhock comes from the old ‘holy hoc’, holy mallow.
• Hollyhock belongs to the mallow family: their round, flat seed discs look like little cheeses.