How to grow hollyhocks
Find all you need to know about growing hollyhocks, in this detailed Grow Guide.
Hollyhocks, Alcea, have long been associated with cottage gardens. Perfect for the back of a border, they grow up to 2m in height. Each stem bears masses of open, bee-friendly flowers measuring up to 10cm in diameter, from July to September. Hollyhocks are biennial or short-lived perennials. In the first year they put on root and foliage growth and in the second they flower, set seed and then die.
Double hollyhocks are stunning but they don’t have the appeal that single varieties have to pollinating bees. If creating a bee-friendly garden stick to single varieties, where you can see the central part of the flowers.
How to grow hollyhocks
Grow hollyhocks in moist but well-drained, light soil in a sunny spot. Taller varieties may need staking. Let seeds develop after flowering before removing and composting the plants, so you can sow seeds of the following year's hollyhocks without paying a penny for them.
More on growing hollyhocks:
Take a look at our handy hollyhock grow guide, below.
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Where to plant hollyhocks
Hollyhocks do best in a south- or west-facing position in moist but well-drained soil. Chalky, sandy or loamy soils are ideal. Plant them at the back of a border as they can reach heights of 2m or more.
Hollyhocks aren't suitable for growing in pots.
How to plant hollyhocks
Prepare the soil by removing weeds and digging in plenty of well-rotted organic matter. Plant hollyhocks in the ground, firming gently, and water well. Tie them to a stake such as a bamboo cane, in exposed or windy gardens.
Hollyhocks self-seed readily – these seedling can be lifted carefully and replanted in your desired position, to flower the following year.
How to propagate hollyhocks
Hollyhocks are easy to grow from seed in spring. Prepare a seed tray with peat-free seed compost and water well, allowing the water to drain. The seeds are large enough to space evenly on the compost surface. Place them about 1.5cm apart from the next. Sieve seed compost over the seeds. Ideally place the tray in a propagator set at about 15-20°C.
In about 2 weeks you should see signs of germination. It can take a further five weeks before plants are ready to prick out. The plants should be ready to plant out in June but won’t flower until the following year.
Alternatively, sow seed in summer, and plant out in autumn. These plants should flower the following year.
If you are using seeds that you have collected yourself from hollyhocks that have finished flowering, seeds from perennial varieties are best sown straight away, as they need a period of cold to help them germinate. Seeds saved from biennial types are best stored somewhere cool and dry, and sown the following year.
Caring for hollyhocks
Hollyhocks need very little care. Stake flowering plants and water in dry weather. After flowering. cut the flower spike off once the seeds have dispersed.
Discover the three Golden Rules of growing hollyhocks, in this video featuring hollyhock expert, Mary Baker:
Growing hollyhocks: problem solving
Hollyhocks can be susceptible to hollyhock rust. This is easy to spot as the leaves and stems will be covered in orange-brown spots. In extreme cases the plant will die. The first signs of the problem are visible on the undersides of the leaves.
Remove infected leaves as soon as you spot them and burn them. In autumn clear away and destroy any fallen leaves as the fungus will overwinter in the soil.
Hollyhock varieties to grow
- Alcea ‘Rosea Nigra’ – deep maroon flowers from June to September. Reaches a height of 2m
- Alcea ‘Halo Mixed’ – a mix of white, purple and pink single flowers held on 2m high stems. Flowers from June to July
- Alcea ‘Chater’s Double Icicle’ – a pure white double with flowers that resemble puff palls. Flowers from July to September. Reaches a height of 1.5m
- Alcea ‘Black Knight’ – nearly black, single flowers anytime from June to September. Reaches a height of 2m
- Alcea rosea ‘Crème de Cassis’ – purple semi-double flowers with a white rim. Flowers from June to September. Height 2m