Hollyhocks: the straight skinny

Flower & Garden Magazine, August-Sept, 1996 by Mary N. Ganter

Holyhocks Are Almost As easy to grow as sunflowers and would probably be grown as often if more gardeners were aware of their good nature. Unlike delphiniums, clematis, poppies and other dramatic flowers that are simpler to admire than to actually grow, hollyhocks need no coddling. The only significant obstacle to success with hollyhocks, a foliar rust disease, can be prevented easily. In sum, their character is superior to their reputation and they are best praised by being grown.

The common hollyhock is Alcea rosea, a member of the mallow family. A related herb, Althaea officinalis or marsh mallow, was called "hock leaf" in medieval England because the leaves were used to treat swelling in horses' hocks or humans' ankles. When Alcea was introduced, perhaps by Crusaders returning from the Holy Land, it was given the name "holyhock" to distinguish it from the older form. Their beauty and utility secured hollyhocks a place in nearly every cottage garden and they were among the first plants introduced to North America by English colonists.

Hollyhocks are true biennials but they may be treated as annuals or perennials according to variety and management. Some outstanding old-fashioned types are `The Watchman,' a dark maroon heirloom, `Indian Spring,' with single or semidouble flowers in white or pink, and `Country Garden' in mixed colors.

To raise hollyhocks as biennials, sow seeds outdoors in a cold frame, nursery bed or other convenient place in late summer or early fall but at least two months before frost. The seeds will sprout quickly and form several large leaves before winter. Give the plants a protective winter mulch. In early spring they should be transplanted into flowering position. Handled in this way, hollyhocks will bloom by midsummer in Zones 3 through 8. In Zones 9 and 10, young plants are set out in the fall and bloom in spring.

Hollyhocks begin flowering low on the stalk, with blossoms opening progressively higher on the stem through the season. Unless you intend to collect seed, plants of biennial varieties can be removed when flowering ceases. Since neighboring hollyhocks readily cross-pollinate, seed gathered from groups of mixed-color plants seldom bears true. Wide spacing and single-color plantings are the best means (short of division) to ensure true-color descendants.

Perennial hollyhocks begin life in the way already described: summer planting, winter mulching and spring transplanting. Zones 9 and 10 do not suit the perennial types; there they are raised as biennials. Because hollyhocks put out a taproot, they must be transplanted before they become at all large. Space them 2-1/2 to 3 feet apart to allow air to circulate; crowding promotes disease in hollyhocks. Because they are heavy feeders and thirsty besides, the perennials thrive best in soil enriched with manure and peat. They will stand dry conditions but prefer moisture. All hollyhocks require at least one-half day of sunlight.

Perennial hollyhocks flower from late June to August. Remove the spent blooms to maintain vigor. In fall, cut the stalks to the ground, taking care not to damage or expose the growth buds at the plant's crown. When winter mulch is removed in spring, check for plants that might have been heaved from the ground and re-cover them with a layer of fresh soil.

At best, hollyhocks are short-lived perennials. Daughter plants grow well from the mother root for only two or three years and during this period they are prone to rust, a fungal disease. Most serious in humid climates and crowded conditions, this fungus manifests itself as dark brown bumps ringed with yellow on hollyhock foliage; the flowers are unaffected. Rust rarely kills, but it is ugly and spreads readily and should not be ignored. Affected leaves should be removed and destroyed, not composted or left on the ground. The problem is more easily prevented than cured: widely spaced plants anchored in loose, rich, well-drained soil can effectively defend themselves. If you are concerned about the vigor of your plants, a simple rust-prevention measure is to remove the basal leaves in early spring. These lower leaves are the most likely to be infected with soil-borne spores. One perennial hollyhock, Alcea rugosa, is said to be resistant to rust.

Annual hollyhocks seldom have problems with rust; they complete their life cycle before the fungus exploits them. Generous spacing is still a good precaution, though soil condition is less critical for the annuals. These types are planted very early, usually indoors, by March. They are transplanted as seedlings into flowering position as soon as the frost danger passes, or earlier if some protection is possible. Annual hollyhocks will bloom from August to October and may self-seed if left to ripen. The original plants will not perform again and should be removed. The annuals offer the most variety of form: `Summer Carnival' and `Powder Puffs' are fully double and `Majorette' is a semidouble dwarf.

Most hollyhocks, including perennial and old-fashioned types, achieve 5 to 8 feet at maturity. Naturally tall and slender, hollyhocks have traditionally taken their place in the back of a border, in the middle of an island bed, beside a wall or along a fence -- but don't hesitate to experiment with other uses. Generally, they are planted in odd-numbered groups to avoid a regimented effect. If regimented is what you like, however, hollyhocks happily oblige; the German poet Goethe had a double row of them lining the drive to his house and was apparently delighted with the effect. If you have only a little space, use only a few plants: in an odd corner, among shrubbery or as punctuation in a cottage garden. Hollyhocks do not mass to good effect, particularly in small spaces.