Hollyhocks (Althaea rosea) - Garden Basics - Flower - Perennial
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Plant Information Type: annual, perennial, biennial
Light: full sun
Flower Color: various
Bloom Time: late summer and autumn
Height: 3-7 feet
Width: 2 feet
Soil Requirements: not too rich
Uses: bed, back of border border
This hardy and reliable cottage garden plant makes a perfect backdrop for your mixed borders, and adds structure to the casual garden. Hollyhocks look especially nice when colors are mixed. They come in white, yellow, pink, red and crimson, with both single and double strains available. Plants sizes vary greatly--from 2½ to 7 feet in height, and the tall spikes are covered with flowers from midsummer to fall.
Although it is actually a perennial, it is sometimes grown as a biennial and discarded after flowering to avoid rust infestation, although some of the newer varieties resist rust. Early flowering strains are sometimes treated as annuals.
Hollyhocks are easy to start from seed. Start them indoors 6-8 weeks before the last frost or sow directly in the garden when the soil is workable. Set out larger, nursery-grown plants in spring for summer bloom or smaller ones in fall for bloom next year. Plants should be spaced two feet apart. The ideal location will have average soil and lots of sun. Rich soil will promote tender growth that is weak and will need staking. These weaker plants will be prone to disease. Most hollyhocks self-sow readily if you let a few flowers go to seed. Most varieties need to be staked in windy areas.
Spider mites can be hosed off and Japanese beetles can be handpicked or if they become a problem. Rust disease shows up as reddish spots on the leaves and stems and can quickly disfigure or destroy a planting. Removing infected and dead leaves can help.