An endless supply of blossoms! Home flower gardeners enjoy growing hollyhocks in borders or against walls and fences where their spectacular flowers stand tall above all else.
The classic variety (Alcea rosea) has graced cottage gardens, outbuildings, and farmsteads for more than a century. Butterflies and hummingbirds find them very appealing!
Large, showy blooms of white, light pink, magenta, light yellow, and burgundy completely cover sturdy 4- to 9-foot tall stalks.
Hollyhock plants are considered biennial, that is, they grow foliage the first year; flower, produce seeds, and die the second year.
These old-time garden favorites reseed themselves freely and flourish in sunny locations that are protected from wind and not too dry. Plants usually do not require staking.
Fun fact: Hollyhocks are closely related to okra, cotton, and hibiscus.
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Botanical Name: Alcea spp.
Common Name: Hollyhocks
Family: Malvaceae
Plant Type: Herbaceous, Perennial, Biennial
Hardiness Zones: 2-10, USA
Sun Exposure: Full sun to partial shade
Soil Type: Moist, Well-drained
Soil pH: Acid, Neutral, Alkaline
Maturity: 365 days or more from seed to flower
Height: 4 to 9 feet
Spacing: 18 to 36 inches apart in all directions
Bloom Time: Summer
Flower Color: Various including yellow, pink, purple, white, and salmon
Quick Guide: Planting, Growing & Caring for Hollyhocks
- Enjoy a colorful show of flowers deep to vibrant colors
- Plant seeds outdoors in full sun to part shade
- Keep well watered; fertilize regularly for prolific blooms
- Plan for stalks up to 9 ft. tall
- Will self-seed; blooms early to late summer
Hollyhock Care
Hollyhock (Alcea rosea) is a classic garden plant that blooms with numerous flowers on tall spikes in midsummer.
Many of the most common varieties are biennials, which means they live for two years and come in a wide variety of colors.
The first year is spent on foliage growth, while in the second year, stems grow, flowers bloom, and seeds develop.
But there are also many varieties that act like short-lived perennials and will flower in their first year if they are planted early enough in the spring or started indoors in the winter.
Hollyhocks do not require much maintenance other than staking and cutting the stalks back after flowering, but they must be protected from insects and fungal diseases such as rust.
They serve as a host plant for painted lady butterfly caterpillars and attract other pollinators such as bees, hummingbirds, and butterflies.
Light
Most hollyhocks can tolerate shade, but they prefer full sun. In locations with excessive shade, these tall plants may flop.
If you live in a hot and dry area, the lower leaves on your hollyhock won’t dry out if you put it in a spot with partial shade.
Soil
Hollyhocks can thrive in a wide range of soil conditions. While rich, well-drained soil is ideal, adding organic matter can often boost your plants’ growth in less-than-ideal growing conditions.
This will also improve air circulation and drainage.
Water
Water regularly and keep the soil moist when starting hollyhocks. However, once established, they are relatively drought resistant.
Avoid wetting the foliage when you are watering; doing so can cause diseased leaves.
Temperature and Humidity
Temperate climates are ideal for growing these plants.
Although some species can withstand temperatures as low as 0 degrees Fahrenheit, they are not particularly cold-hardy, and early fall frosts can harm late blooms.
Due to their susceptibility to rust, these plants do not prefer high humidity.
Fertilizer
Hollyhocks prefer fertile conditions and thrive in soils with high levels of nutrients. Without it, you may observe yellowing foliage and fewer blooms.
If your soil isn’t rich, a light application of fertilizer or compost in the spring can help.
Pruning
Individual hollyhock flowers can be removed as they fade, and entire stalks can be cut back to the ground once flowering has finished. This will prevent the formation of seed heads and reseeding.
But if you want seeds for next spring, leave the flowers and a few stalks on the plant until the seeds have dropped.
They will die back in the winter, and all stems and leaves should be cut back to the ground to prevent the spread of rust disease.
Overwintering
Depending on where you live, you may need to give your Hollyhocks special winter care. It is best to prune stems and leaves before the fall in any area.
In frost-prone environments, you must protect the roots of your Hollyhocks by layering organic material over the root zone.
Hollyhocks can be grown as annuals in hard freeze zones by starting seeds in containers and overwintering them indoors.
Water them sparingly during the winter and gradually reintroduce them to the outdoors as the weather warms up.
In areas where they can be left outside, prune them in the fall to about 6 inches above the ground. Cover the roots and base of the plant with 4 to 6 inches of straw or mulch.
In the spring, remove the mulch slowly, layer by layer, to give the roots time to adjust. Once you see new growth, remove all the straw or mulch.
Cover again in case it freezes in the spring.
How to Plant and Grow Hollyhock
Site Preparation
Hollyhocks will thrive in full sun to partial shade and rich, moist soil.
Prior to planting work plenty of organic matter, such as compost or aged animal manure, into the garden. This helps condition the soil, which improves drainage and increases its ability to hold water and nutrient.
Watch our video 6 Tips for Growing Great Flowers to learn more.
How to Plant Hollyhock Seeds
Sow hollyhock seeds outdoors just beneath the surface of the soil 1-2 weeks before the last frost. Seeds will germinate in 10-14 days. Thin to 18-36 inches apart after seedlings have sprouted.
Since hollyhocks have long taproots, it is best to start indoor hollyhock seeds in tall, individual pots and transplant them as soon as possible to prevent damage.
Water as needed during dry conditions to keep flowers blooming. Adding an organic flower fertilizer every few weeks will result in bigger, bolder blooms. When flowers fade, cut stalks to the ground.
Seed Saving Instructions
Hollyhocks will cross-pollinate. Gardeners should only raise one variety at a time to save pure seed or isolate varieties by 1/4 mile.
Seeds are ready to harvest when the seed capsules are completely dry and brown. The capsules can then be picked and the seeds easily separated from the paper-like husk.
Common Pests and Plant Disease
Hollyhocks are vulnerable to a number of garden pests including thrips, Japanese beetles, sawflies , and spider mites. Watch closely, and if problems exist treat with organic pesticides for immediate control.
They are vulnerable to hollyhock rust, an infection caused by a fungus that starts out as yellow spots on leaves before turning into brown or rust-colored bumps on the underside of the leaves.
Keeping rust at bay is much easier than dealing with a full-blown outbreak. Stopping rust will be a lot easier if you water from below, make sure there is good air circulation, and clean up well at the end of the fall.
Leaves that show signs of rust should be taken off the plant and disposed off to prevent the disease from spreading.
Foliage is susceptible to other fungal diseases as well, such as anthracnose and powdery mildew, which can disfigure the leaves under severe infestations.
To reduce plant diseases common to hollyhock:
- Avoid overhead watering whenever possible (use soaker hoses or drip irrigation)
- Properly space plants to improve air circulation
- Apply copper or sulfur sprays to prevent further infection
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