When to plant hollyhock seeds – you have two windows a year to choose from

Knowing when to plant hollyhock seeds is key if you want to add these cottage garden favourites to your garden. Hollyhocks are loved for their towering height, beautiful flowers and popularity with wildlife, plus, they're really easy to grow, so long as you know when to plant hollyhock seeds.

Hollyhock seeds are one of the things to plant in October; however, if you've missed this window, you can also plant hollyhock seeds in early summer, although how you plant in each window slightly differs.

For direct sowing, October is the ideal time to plant hollyhock seeds. This makes sense as the plant naturally disperses its seeds during September and October. However, they can also be planted directly outside in early summer – planting in May or June is ideal – once all chance of frost has passed.

Experts at Thompson & Morgan also suggest an alternative method. 'Sow hollyhocks in late summer in a cool greenhouse and overwinter the plants in cool, well-lit conditions. Then plant out the following spring. This produces larger plants and is recommended if the soil is heavy or badly drained.'

Along with knowing when to plant hollyhock seeds, it is also important that you know how to sow seeds for the greatest chance of success.

If your seeds aren't germinating – the first thing you should check is when to plant hollyhock seeds. Plant them too early and the seedlings will be at risk of frost, plant them too late and the ground will be too dry.

Other factors to consider is the depth of sowing and whether they are receiving enough light and water.

Once they've germinated and taken root you should have some pretty impressive blooms. 'Hollyhocks are a traditional choice with spires of open, saucer-shaped flowers blooming in July. With well-drained reasonably fertile soil and positioned in full sun, they can reach heights of 2m,' says garden expert Leigh Clapp.

Where to buy hollyhocks

• Crocus: try the Alcea rosea 'Single mixture' 
• Sarah Raven: the Alcalthaea suffrutescens 'Parkrondell' is very easy to grow
• Thompson & Morgan: there are plenty of stunning hollyhock varieties to choose from

FAQs

What is the lifespan of a hollyhock flower?

The lifespan of a hollyhock flower is two years as hollyhocks are biennial plants.

'During the first year, the biennial plant typically produces a rosette of leaves close to the ground and stores energy in its roots or stems,' explains Julian Palphramand, Head of Plants at British Garden Centres.

'In the second year, the plant develops a flowering stalk, produces flowers, sets seeds, and then dies. After the seeds are dispersed, the life cycle begins again with new seedlings sprouting the following year'.

This means you must plant the seeds the year before before you want blooms. If you want hollyhock flowers this year, then you can purchase established plants that will behave like annuals. The same rules apply to when to plant foxglove seeds – another popular biennial plant.

For consistent blooms, succession planting is recommended. This means you sow seeds in the first year and the second year. This will ensure you get blooms every year, rather than every other year. Once you've done both of these plantings, self-seeding can do the rest of the work.

Do hollyhocks self seed in the UK?

Yes, hollyhocks self-seed in the UK. This means once you've got established plants, you no longer need to worry about when to plant hollyhock seeds.

One of the benefits of hollyhocks is that they produce lots of seeds. Know how to collect seeds and you'll have more than enough to populate your own garden, as well as share with family and friends.