Notes on Growing Hollyhocks

Hollyhocks are flowering biennial or short-lived perennial plants typically grown in cottage gardens.

I usually start hollyhock seeds in seed trays or punnets of seed raising mix in late summer, transplanting seedlings into small pots when the first pair of true leaves appear. Germination takes 1-2 weeks. When they’ve reached a manageable size in mid-autumn (and are large enough to fend for themselves!) these can then be planted into beds and borders. I have found that hollyhocks do well planted in groups of 3 quite close together (30-40cm) which seems to shelter the cluster of plants and reduces the need to stake. 

Hollyhock plants do best if planted in the ground by the end of autumn, so they have the whole winter to slowly become established. They spend their first year storing nutrients and growing taproots into the soil, and then use this energy the following spring to send up their distinctive flowering columns. In spring, mature plants will send up a flower stalk with blossoms beginning to unfurl midway up the stem and slowly working their way towards the top, providing a gorgeous, long-lasting display of colour.

Flowering continues towards the end of the growing season in summer, with seed heads developing along the stalk. Ripened seeds will turn dark brown/black, which can be collected and stored in a paper bag. The stalk will also dry out and turn brown, after which it can be cut back to about four inches from the ground. Care should be taken not to damage the leafy clump at the base, which will remain through the following winter. Hollyhocks may send up a flower stalk in their first spring, but more commonly do so in the second year when the plant is more mature. The second year of flowering is usually the most vigorous, with either a taller stalk or multiple shorter ones. Hollyhocks are normally pulled out after their second year of flowering, although healthy specimens may sometimes provide a reasonably good display in their third year. 

If you are new to growing hollyhocks, be prepared for the inevitable appearance of Puccinia malvacearum, the rust fungus that has universally attached itself to hollyhocks in every part of the world for the last 150 years. Since the appearance of this disease, gardeners no longer grow hollyhocks from divisions or cuttings; they are now always grown from seed. To reduce the impact of disease, allow plenty of airflow around the plants, mulch well to keep the humidity low around the base of the plant, and water the roots rather than the leaves.

Hollyhocks prefer a sunny position and soil rich in organic matter. In our garden, some of the healthiest specimens began life as self-sown seedlings popping up in the lawn and on gravel paths. Our tallest, however, grew in the rich soil of our vegie patch.