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Alcea rosea – commonly known as hollyhocks – is an old, colorful garden favourite, often associated with back borders or small gardens. Some cultivars grow to 8 feet (2.4m) or taller with white, pink, rose or yellow flowers 6 inches (15cm) long.
Hollyhocks bloom like hibiscus flowers. They open in a progression from the bottom up. A foot or two of stem can be covered with flowers anytime from summer through fall. Flowers can be single, semi-double, or double.
Hollyhocks are biennial or short-lived perennials. Some biennials such as the cultivars ‘Summer Festival’ and ‘Majorette’ can be considered annuals if they flower in their first year.
Hollyhocks are a favorite garden plant since ancient times. Plant them against a fence, wall or behind a border.
Meet the Hollyhocks – Alcea Rosea
- Type of plant: Perennial plants grown annually or biennially; short-lived perennials depending on the average low temperatures in the area.
- Growing area and range: 3-11
- Hardiness: Annual plant in areas with cold winters; Perennial plant in areas with warm winters; died from high temperature.
- Height and Width: 3 to 6 feet (90-180cm) tall and 1 to 2 feet wide
- Shape: Clusters of large round leaves and thick flower stalks
- Flower shape: Plump flower buses produce bowl-shaped blooms – single, semi-double or double flowers 3 to 5 inches (12.5 cm) wide; The flowers have wrinkled petals that can be white, pink, rose, red, purple, creamy yellow or apricot.
- Flower color: White, pink, rose, red, purple, cream yellow, apricot
- Bloom time: Spring in warm climates; mid-summer in cool climates
- Uses: Makes a great vertical accent; rabbit proof
- Garden companions: Purple coneflowers, black daisies and sunflowers.
- Common names: Hollyhock, malva
- Botanical name: Alcea rosesometimes listed as Rose
- Family: Malvaceae family
- Origin: Temperate regions of Europe and Asia
Where to Grow Hollyhocks — Alcea Rosea
- Plant hollyhocks in full sun or partial shade in very warm areas.
- Plant hollyhocks in rich, well-drained soil. Add compost to the bed before planting hollyhocks.
- Plant mallows at the back of a mixed border or as an accent plant against a fence or wall.
- Hollyhocks prefer soil with a pH between 6.0 and 8.0.
Alcea Rosea — uses of Hollyhock
- Plant against a fence or wall or behind a border.
When to Plant Hollyhocks – Alcea Rosea
- Sow seeds indoors in winter to early spring for summer blooms
- Start hollyhocks indoors from seed in Zones 3 to 8. Sow seeds 2 to 4 weeks before the average last frost date.
- In Zones 9 to 11, start plants in the fall and treat them as biennials.
- Plant the seedlings into the garden a week or two after the last frost.
- Sow mistletoe seeds directly or plant seedlings in the garden after the last frost of spring.
- Plant or direct sow seeds as soon as the soil warms in spring. Direct sown plants may not bloom until the following year.
- Sow seeds in late summer or sow seedlings in fall in Zones 9 to 11 for spring blooms.
Planting and Spacing Hollyhocks — Alcea Rosea
- Sow seeds 1/4 inch deep. Indoors, sow one seed per pot. Seeds germinate in about 10 days and grow rapidly.
- Sow seeds outdoors in spring or summer; Plant seeds 3 inches (7.6cm) apart.
- Thin or transplant seedlings when they are a few inches tall.
- Place the plants in the garden where they will grow; Distance between plants from 12 to 24 inches (30-61cm)
Watering and Fertilizing Hollyhocks
- Water hollyhocks regularly to keep the soil moist; The soil can get a little drier in the summer.
- Fertilize the plant at planting time and feed every 4 or 5 weeks while the plant is growing. Mulch the bed with compost or leaf mold each fall.
- Cover hollyhocks to avoid soil splashes that can spread fungal diseases. Remove any leaves infected with rust immediately.
Hollyhock — Alcea Rosea Care
- Stake hollyhocks high to keep them upright.
- After the first flowers fade, cut the stems just above ground level; continue feeding and watering to encourage flowering in late summer or early fall.
- Remove the stems after the flowers have finished blooming unless you want to save the seeds.
- Spread mulch around plants to prevent soil-borne diseases.
- Protect plants in winter by covering with 2 inches (5 cm) of chopped leaves.
Hollyhock – Alcea Rosea Pest
- Hollyhocks are susceptible to rust, a fungal disease. Spray fungicide. Uproot severely infected plants.
- Hollyhocks can be attacked by Japanese beetles. Watch for slugs and snails.
Hollyhock — Propagation of Alcea Rosea
- Sow seeds in spring or early summer. Some varieties bloom the first year from seed when planted outdoors in spring.
- Germination takes about 9 days at 55°F (13°C). Plant outside or sow directly as soon as the soil warms in spring. Directly sown plants may not flower until the following year.
- Plants often self-seed.
- Divide roots of large clumps every other spring. Replant immediately after division.
- Side shoots can be separated and rooted.
Hollyhock – Growing Alcea Rosea Varieties
- ‘Chater’s Double’ is a perennial cultivar with double flowers in maroon, red, pink, white or yellow.
- ‘Nigra’ is a single-flowered, dark reddish-brown variety; Can grow up to 5 feet tall.
- ‘Summer Carnival’ blooms from seed sown in early spring and has double flowers.
- ‘Majorette’ is only 2½ feet tall.
Hollyhocks Frequently Asked Questions
Q: Are hollyhocks biennials or perennials? Mine bloom every year.
A: Hollyhocks are biennials, but they are able to reproduce easily from seed and grow back for many years.
Q: What growing conditions are best for mallow plants?
A: Plant hollyhocks in full sun and deep, humus-rich soil. They will grow best if planted near a wall, fence or building where they are protected from the wind.
Q: What causes hibiscus leaves to rust, turn yellow and fall off?
A: What you describe is fungal rust. Fungal spores are produced in small red pustules on the underside of leaves, while yellow areas appear on the upper side. A severe case of rust will cause leaves to turn yellow, wilt and fall off. Remove infected leaves as soon as possible. Clean up fallen leaves. Sprinkle sulfur on the plant in early spring. Make sure to cover the underside of the leaf as well.
