How to grow hollyhocks

Choosing a hollyhock

Hollyhocks are fully hardy and flower in the second year after sowing. They are short-lived

Perennials are any plant living for at least three years. The term is also commonly used for herbaceous perennials which grow for many years (To compare: annual = one year, biennial = two years).

• Have you got a suitable location in the back of a sunny border or along a wall?
• If your garden is windy, choose a sheltered spot and stake your plants as they begin to grow
• Single flowers are best to attract pollinators like bees and butterflies
• Hollyhocks are not long lived so always allow
  A seedling is a young plant grown from seed.

  seedlings to grow and keep the best plants and flower colours
• Choose colours that will compliment your other border plants

Go to RHS Find a Plant  and search for Alcea rosea to browse the photographs and plant descriptions, and find out where to buy them.

RHS guide to assessing your microclimate

RHS guide to assessing your microclimate

RHS guide to identifying your soil type

RHS guide to identifying your soil type

Buying a hollyhock

Hollyhocks are available as seed, small

Seedlings or young plants grown singly in small modules, with the advantage that they can be transplanted with minimal root disturbance. Bedding plants and young veg plants are often sold as plug plants of various sizes, with smaller ones requiring more aftercare. They usually need to be potted up and grown on indoors until large enough to plant outside.

RHS how to choose healthy plants

RHS how to choose healthy plants

Where to plant

Hollyhocks will grow in any garden soil, but prefer fertile, well-drained soil, in full sun, to produce the tallest flower spikes. Choose a position that is sheltered from strong winds, else they tend to blow over.

When to plant

Pot grown hollyhocks are best planted in spring or autumn, but can be planted at any time, spacing them 60cm (24in) apart.

Plug plants, bought in garden centres or online, are best grown on in 10cm (4in) pots to establish a good root system, before planting out into the garden.

If growing hollyhocks from seed sow indoors in mid- to late spring or directly in the position you want them to grow in May/June (See the Propagation section below for more details).

Watering

Staking

If your garden is windy, place a bamboo cane or stout stake close to each stem and tie the stem to the support as it grows.

Feeding

Usually, plants growing in a good garden soil will not need additional feeding. Just improve the soil by adding a 10cm (4in) layer of well-rotted garden compost to the soil where you wish to grow the hollyhocks, and digging it in before planting.

Deadheading

Cut the flower spikes to the ground when the flowers have faded. If you want to save the seed, wait until the seed cases are brown before collecting the seed and then cutting down the stalks.

End of season care

Hollyhocks are full hardy and don’t require any special treatment over winter. Remove all dead leaves and discard plants that have been badly effected by rust disease (see problems below).

No pruning is required, just remove any leaves that are heavily infected with rust disease through the summer and cut down the flower spikes when the flowers have faded.

Hollyhocks are easy to grow from seed and will readily self-seed in your garden. The new plants may not be exactly the same as the parent plants, if they are hybrids or cultivars. Self-seeded plants can be lifted while young and transplanted to a spot in your garden where you would like them to grow.
 

Seed: collecting and storing

Seed: collecting and storing

Sow Hollyhock seeds indoors or in a greenhouse in spring (April/May). They germinate easily in temperatures of 16-21 ⁰ C (61-70⁰ F), so placing in a propagator encourages germination. If the seed pot is placed on a windowsill, germination is just a bit slower. See our guide to sowing seed in-doors

Alternatively, sow seeds directly in the ground where you want them to grow in May/June. Hollyhock seed can also be sown in autumn and the young plants over-wintered in a cold frame or cold greenhouse, to flower the next year.

Young plants are suceptible to damage by slugs and caterpillers. Flee beetles can occassionally cause significant leaf damage.

Hollyhocks are susceptible to rust disease and plants should be replaced after a few years, to prevent a build-up of disease. Collect all dead and diseased tissue at the end of the season to reduce the carry-over of rust spores to the next year.