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How to Grow Alcea Rosea — Hollyhocks

Alcea Rosea or hollyhock, or malva. A double form in pink.
Alcea Rosea or hollyhock, or malva. A double form in pink.

Alcea rosea–commonly called hollyhocks–are a colorful, long-time garden favorite often associated with the back of borders or cottage gardens. Some cultivars grow to 8 feet (2.4m) tall or taller with white, pink, rose, or yellow flowers 6 inches (15cm) across.

Hollyhock flowers resemble hibiscus. They open in progression from the bottom up. A foot or two of the stem can be covered with blooms at any one time from summer through fall. Flowers may be single, semi-double, or double.

Hollyhocks are biennial or short-lived perennials. Some biennials such as the cultivars ‘Summer Carnival’ and ‘Majorette’ can be treated as annuals if they bloom the first year

Hollyhocks are an old-time favorite garden plant. Grow them against a fence or wall or at the back of a borders.

Garden Hollyhock, Alcea rosea

Get to Know Alcea Rosea — Hollyhocks

  • Plant type: Perennial grown as an annual or biennial; short-lived perennial depending on average low temperatures in the region.
  • Growing Zones and range: 3-11
  • Hardiness: Annual in cold winter regions; short-lived perennial in warm-winter regions; killed by heat.
  • Height and width: 3 to 6 feet (90-180cm) tall and 1 to 2 feet wide
  • Form: Large clumps of rounded leaves and thick bloom stalks
  • Flower form: Plump flower bus produce bowl-shaped blooms–single, semi-double, or double flowers 3 to 5 inches (12.5cm) wide; blooms with crinkled petals can be white, pink, rose, red, purple, creamy yellow, or apricot.
  • Flower colors: White, pink, rose, red, purple, creamy yellow, apricot
  • Bloom time: Spring in warm climates; midsummer in cool climates
  • Uses: Excellent vertical accent; rabbit resistant
  • Garden companions: Purple coneflower, black-eyed Susan, and sunflower.
  • Common name: Hollyhock, malva
  • Botanical name: Alcea rosea, sometimes listed as Althaea rosea
  • Family: Malvaceae
  • Origin: Temperate regions of Europe and Asia

Where to Plant Alcea Rosea — Hollyhocks

  • Grow hollyhocks in full sun or part shade in very warm regions.
  • Plant hollyhocks in average to rich, well-drained soil. Add aged compost to the planting bed before setting hollyhocks out.
  • Plant hollyhock at the rear of a mixed border or as an accent plant against a fence or wall.
  • Hollyhocks prefer a soil pH of 6.0 to 8.0.

Alcea Rosea — Hollyhock Uses

  • Plant against a fence or wall or at the back of a border.

When to Plant Alcea Rosea — Hollyhocks

  • Sow seed indoors in winter to early spring for summer bloom
  • Start hollyhocks indoors from seed in Zones 3 to 8. Sow seed 2 to 4 weeks before the last average frost date.
  • In Zones 9 to 11, start plants in the fall and treat them like biennials.
  • Set seedlings in the garden a week or two after the last frost.
  • Sow hollyhock seed directly or set out seedlings in the garden after the last spring frost.
  • Set out plants , or sow seeds directly as soon as the soil has warmed in spring. Direct seeded plants may not bloom until the following yea
  • Sow seed in late summer or set out seedlings in the fall in Zones 9 to 11 for spring blooms.
Flourish hollyhocks in front of an old farm house
Flourish hollyhocks in front of an old farm house

Planting and Spacing Alcea Rosea — Hollyhocks

  • Sow seeds 1/4 inch deep. Indoors, sow seed one per pot. Seeds germinate in about 10 days and grow quickly.
  • Sow seeds outdoors in beds in spring or summer; space seeds 3 inches (7.6cm) apart.
  • Thin or transplant seedling when they are several inches tall.
  • Set plants in the garden where they will grow; space plants 12 to 24 inches (30-61cm) apart

How to Water and Feed Alcea Rosea — Hollyhocks

  • Water hollyhocks frequently to keep the soil just moist; the soil can be somewhat drier in summer.
  • Fertilize plants at planting time and feed them every 4 or 5 weeks throughout their growth. Topdress beds with compost or leaf mold each fall.
  • Mulch hollyhocks to prevent splashing soil which could transfer fungal diseases. Remove rust infected leaves immediately.

Alcea Rosea — Hollyhock Care

  • Stake tall hollyhocks to keep plants upright.
  • After first blooms fade, cut the stalks just above the ground; continue to feed and water plants to encourage late summer or early fall rebloom.
  • Remove stalks after bloom is finished unless you want to save the seed.
  • Mulch around plants to prevent soil-borne diseases.
  • Protect plants in winter by mulching 2 inches (5cm) of chopped leaves.

Alcea Rosea — Hollyhock Pests and Diseases

  • Hollyhocks are prone to rust, a fungal disease. Spray with a fungicide. Pull plants that are seriously infected.
  • Hollyhocks can be attacked by Japanese beetles. Watch for slugs and snails.

Alcea Rosea — Hollyhock Propagation

  • Sow seeds in spring or early summer. Some varieties bloom the first year from seeds own outdoors in spring.
  • Germination takes about 9 days at 55°F (13°C). Set out plants , or sow seeds directly as soon as the soil has warmed in spring. Direct seeded plants may not bloom until the following year.
  • Plants often self sow.
  • Divide roots of large clumps every other year in spring. Replant division immediately.
  • Side shoots can be separated and rooted.

Alcear Rosea — Hollyhock Cultivars to Grow

  • ‘Chater’s Double’ is a perennial strain that has double flowers in maroon, red, rose, white, or yellow.
  • ‘Nigra’ is a single-flowered, deep maroon cultivar; grow to 5 feet.
  • ‘Summer Carnival’ blooms from seed sown in early spring, has double flowers.
  • ‘Majorette’ grows just 2½ feet tall.

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