How to grow Althaea
Referring to its medicinal use, from the Greek althaea, to cure (Malvaceae). genus of easily grown plants comprising annuals, biennials and perennials.
Biennial species cultivated A. ficifolia (fig-leaved or Antwerp hollyhock), to 6 feet, single or double flowers in spikes of mostly yellow, June. A. rosea, hollyhock, erect-growing, to 9 feet or sometimes a good deal more. Tall • spikes of single or double flowers, sometimes 3 inches or more across, in shades of red, pink, yellow and white, July. This is strictly a perennial but is often treated as a biennial.
Perennial species cultivated A. cannabina, 5-6 feet, rose flowers, June; var. narbonensis, red flowers. A. officinalis (marsh mallow), 4 feet, blush-coloured flowers, July, native to British marshes.
Cultivars of hollyhocks `Chater’s Improved’, fully double flowers, mixed colours. ‘Apple Blossom’, apple-blossom pink. `Carmine Rose’, double cherry-red flowers; and other separate colours. ‘Allegheny Mammoth’, mixed colours, single and semi-double. ‘Begonia Flowered’, fringed petals with central rosette, mixed. Annual hollyhock: ‘Triumph Supreme’, to 4 feet, compact growing.
Hollyhocks will succeed in most soils, but prefer the heavier kinds, especially if they are enriched. They need plenty of water in dry periods and should be firmly staked with stout stakes 7 feet or more long, driven well into the ground, to prevent wind damage, particularly in exposed gardens. Stems should be cut down to within about 6 inches of the ground after flowering is over.