With dramatic flower stalks and attractive grey-green leaves, hollyhocks are a cottage garden favourite. Hollyhocks are a biennial, meaning they grow foliage the first year, go dormant over the winter, form flowers and set seed the second year, then die. While a few hollyhocks are true annuals, meaning they will flower the same year they germinate from seeds, most cultivars are biennial plants.
Hollyhock's first year
Hollyhock's first year is all about storing enough energy to flower in the second year. Seed is sowed in early spring directly into the garden after all danger of frost has passed. The seed germinates and a rosette of oval or slightly lobed leaves forms. As temperatures grow colder in the fall, the plant goes dormant. It is possible to sow seeds in early fall, six to eight weeks before the first frost date, so the seeds germinate, go dormant over winter and flower the following year.
Hollyhock's second year
Hollyhock leaves are quite handsome, but the flowers are spectacular. In early to mid summer flower stalks begin to emerge from the rosette of leaves. The flower stalks may reach 9 feet in height; depending on the variety, although even the dwarf varieties are usually 2 to 4 feet tall. The flowers begin to open along the stalk, typically from the bottom up, in mid summer. Individual blooms can last from one to four weeks depending on variety. Hollyhock flower stalks show blooms in all stages, bud, full bloom and fading flower.
As the blooms fade, deadhead the flowers. This means remove the fading flowers to encourage the plant to continue to produce blooms. By deadheading the faded flowers your hollyhock will continue to bloom through early fall. Do not damage the flowering stalk while deadheading, once the flowering stalk is gone your hollyhock will stop flowering. Deadheading works by diverting energy that would normally go into ripening seeds back to producing blooms.
Hollyhocks readily self sow. This means, as the flower fades, the seeds in the flower begin to ripen. In early fall the seeds fall from the parent plant into the soil. In several years, if you allow your hollyhocks to self sow, you can have a block of hollyhocks in all stages of growth (first year vegetative and second year flowering). You will have to sacrifice some bloom time, for if you deadhead flowers, you remove the seeds. Choose one or two flower stalks and allow them to set seed to keep your hollyhock patch growing and deadhead the rest for continuous blooming.
Landscaping with Hollyhocks
Hollyhocks are tall plants, ranging from 2 feet to 8 or 9 feet. Use them as back-of-the-border plants. Or, if you plant a few in the middle of a perennial bed, they add height in an unexpected place and small plants can peek around the foliage. Hollyhocks also work well growing against fences, particularly post and rail fences, barns and other outbuildings. Use hollyhocks to screen unsightly landscape features like air conditioning units, propane tanks and dustbins. Hollyhocks can have either single or double blooms with flower colours of white, yellow, purple, red, rose, pink and apricot.