Alcea rosea (common hollyhock) is an ornamental plant in the Malvaceae family. It was imported into Europe from southwestern China during, or possibly before, the 15th century. William Turner, a herbalist of the time, gave it the name "holyoke" from which the English name derives.
Alcea rosea is variously described as a biennial (having a two-year life cycle), as an annual, or as a short-lived perennial. It frequently self-sows, which may create a perception that the plants are perennial. The plant may flower during its first year when sown early. It will grow in a wide range of soils, and can easily reach a height of about 8 feet (2.4 m).
The flowers are a range of colours from white to dark red, including pink, yellow and orange. Different colours prefer different soils. The darker red variety seems to favour sandy soils, while the lighter colour seems to favour clay soils. The plants are easily grown from seed, and readily self-seed. However, tender plants, whether young from seed or from old stock, may be wiped out by slugs and snails. The foliage is subject to attack from rust (Puccinia malvacearum), which may be treated with fungicides. Commercial growers have reported that some closely related species (Althaea rugosa and Althaea ficifolia) are resistant to this fungus.
- "Alcea rosea". Tropicos. Missouri Botanical Garden. Retrieved 18 April 2017.
- "Flora of China 12: 267–268. 2007" (PDF). Harvard University. Retrieved 2011-07-21.
- "Hollyhock". Cornell University. Retrieved 2011-07-21.
- "Annual - Hollyhock - Althaea rosea". University of Illinois. Retrieved 2011-07-21.
- "Plant of the Month - Hollyhocks" (PDF). New Mexico State University Master Gardener Newsletter. Archived from the original (PDF) on 2011-10-07. Retrieved 2011-07-21.
- "Hollyhock rust". Cornell University. Archived from the original on 22 June 2009. Retrieved 2009-07-15.
- "Yard & Garden Line News". University of Minnesota Extension Service. 2005-06-15. Archived from the original on 2010-03-22. Retrieved 2010-02-05.
- Howard, Michael. Traditional Folk Remedies (Century, 1987) p.155
|Wikimedia Commons has media related to Alcea rosea.|