Ornamental · Malvaceae
Hollyhock
Alcea rosea
Towering columns of wide, saucer-shaped flowers that sow the next generation from their own dry seed heads.
Full sun
Every 5–7 days
USDA 3–9
5–8 ft · 1.5–2.4 m
Overview
Hollyhock is the cottage-garden classic, a mallow-family plant that throws up a single tall, hairy stalk clear past 8 feet (244 cm) and studs it with wide, saucer-shaped flowers from June through August. Each bloom opens flat and open-faced along the spike, stacked one above the next up the stem, so the whole column reads as a ladder of color rising against a fence or back wall.
The plant is easy to grow for all its height. Most forms are biennials, so the first year builds only a low, spreading rosette of broad, rough-textured leaves close to the ground, and the flowering spike shoots up in the second year. It self-seeds hard from dry, flat-packed seed heads, so an established stand keeps refilling itself.
The one feature every hollyhock grower comes to know is rust, a leaf fungus that follows the plant almost everywhere and speckles the foliage with orange and rusty marks. Give the plants full sun, room for air to move between the leaves, and water at the roots rather than over the top, and the foliage stays cleaner while the flowers carry on up the stalk.
Care
The short version: hollyhocks need a full-sun position, organically rich loam with sharp drainage, steady water applied low so the broad leaves stay dry, and wide spacing that lets air wash between the tall stalks and hold rust back.
Light
Hollyhocks want full sun to flower their fullest and hold their tall spikes upright without leaning. They take a little partial shade, but in too much shade the stalks stretch thin, lean over, and carry only sparse blooms.
Water
Give them average, even moisture rather than letting the soil swing from soaked to bone dry. Water low at the base with a soaker hose or drip line so the broad leaves stay dry, which is one of the best ways to keep the orange rust marks at bay. They will not tolerate wet, soggy soil over winter.
Soil
Plant them in average, rich, well-drained loam worked with some compost. They are easygoing about pH and grow well anywhere from 6.0 to 8.0, so sharp drainage matters far more than the exact reading.
Humidity
Ordinary outdoor humidity suits them fine, so there is no number to chase. What counts here is airflow, since still, damp air trapped among the large, crowded leaves is exactly what rust needs to take hold.
Feeding
A single feed in spring is plenty. Work in compost or a balanced general-purpose fertilizer as growth starts and the new leaves push, and the plants carry themselves through the season from there.
Pruning
Cut the spent flower spikes once the blooms fade to neaten the plant or to rein in self-seeding if it spreads more than you would like. Just as important, strip off and destroy any rust-spotted lower leaves and clear all the old debris in fall so the fungus cannot overwinter.
Size & spacing
These are tall, narrow plants, running 5 to 8 feet (152 to 244 cm) high on their single spike while the leafy base holds to just 12 to 24 inches (30 to 61 cm) across. Give each one that full spread of room so air moves freely between the broad leaves and rust has a harder time spreading.
When to plant
Hollyhocks run on a two-year clock. Sow the seed in late summer or start it indoors in late winter, set young plants out after the last spring frost, and the wide, saucer-shaped flowers open along the spike from June through August of the following year.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Late winter to early spring, about 8 to 10 weeks before the last frost.
- Plant: After the last spring frost once soil has warmed.
- Harvest: June through August.
Hardiness
USDA hardiness zones: 3–9
Temperature: down to -40°C
Troubleshooting
Almost every hollyhock problem shows itself on the leaves, and rust is the first you will see, freckling the foliage with orange. Match the marks you find below, then act early, since most of these are easier to head off than to cure once they spread.
Orange flecks above, rusty pustules below
The marks belong to hollyhock rust, the one disease that trails this plant almost everywhere. On the upper leaf you see scattered yellow-orange spots, and turning a leaf reveals raised, brown to dark-red pustules studding the underside right below them. The hardest-hit leaves punch through with holes and then curl and shrivel dry. Strip the spotted leaves the moment they show, water low at the base so the foliage stays dry, and clear away every fallen scrap in fall so the spores have nowhere to overwinter.
Fix:
- Remove and destroy symptomatic leaves early
- Clear all hollyhock debris in fall
- Water at the base to keep foliage dry
- Remove weedy mallows nearby
- Apply a labeled fungicide before symptoms appear if rust is recurrent
Leaves eaten to a lacy skeleton
When the foliage thins to lace, two chewers are behind it. Japanese beetles, metallic green and bronze, cluster on the leaves in daylight and eat the soft tissue until only the fine vein network remains. Slugs work in the dark and betray their route with glistening slime trails. Drop the beetles into soapy water in the early morning, and set baits or traps along the paths the slugs travel.
Fix:
- Hand-pick beetles into soapy water in early morning
- Reduce nearby turf grub habitat
- Use slug baits or traps where slugs are present
Fewer blooms and pinholes in the buds
The offender is the hollyhock weevil, a tiny black insect with tan to orange legs and a long, thin snout, easiest to spot perched on the round buds and open flowers. It drills pinholes into the buds and the developing seeds, which quietly thins the bloom. Shake the little weevils onto a sheet and destroy them, then clear off the dry seed heads where their larvae grow up.
Fix:
- Hand-pick or shake weevils onto a sheet and destroy them
- Remove and destroy old seed heads where larvae develop
Ragged lower leaves stippled with dark spots
Leaf spot and anthracnose fungi mottle the lower leaves with dark spots and blotches when plants stand crowded, stressed, or wet from overhead watering, while the flowers overhead stay clean. The bottom of the plant looks ragged and tattered, though it is rarely in real danger. Pick off the worst-marked leaves, open the spacing so air moves, and water at the base rather than over the top.
Fix:
- Remove affected leaves
- Improve air circulation
- Water at the base rather than overhead
Toxicity
Good news for households with pets: the ASPCA lists hollyhock as non-toxic to cats, dogs, and horses, and the wide flowers are safe enough that people eat them. The only thing to watch is the bristly, hair-covered leaves and coarse fibers, which can leave a mild skin rash on sensitive people, so it is worth pulling on gloves before you handle or cut the plants.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The ASPCA lists hollyhock as non-toxic to cats, so a curious bite of leaf or petal will not poison one. A cat that gorges on any plant may bring some fiber back up, but the tissue itself holds nothing to fear.
Dogs None
Dogs are safe here too. Hollyhock is non-toxic to dogs, and the coarse, hairy leaves might give a leaf-chewing pup a brief, mild stomach upset from the roughage at worst.
Horses None
Horses can graze right up against the broad, bristly leaves without worry, since the plant carries no toxic principles for them.
Rabbits Safe
A rabbit can nibble the rough foliage and the wide petals without trouble, since nothing in this mallow-family plant will do it harm.
Livestock Safe
Cattle, goats, and sheep face no toxic risk from hollyhock if they browse the leaves and stems in a pasture or at the garden edge.
Birds Safe
Backyard birds and poultry can peck at the foliage and the flat, packed seeds without any harm.
People Safe
The plant is safe for people, and the wide, saucer-shaped flowers are even edible, used as a garnish or steeped for tea. The one caveat lies in the leaves and stems: their bristly hairs and coarse fibers can leave a mild skin rash on sensitive skin, so it is worth wearing gloves when you handle or cut them.
Contact with the bristly foliage and plant fibers can cause skin irritation (contact dermatitis) in sensitive people; wear gloves when handling.
Varieties
Most garden hollyhocks are the common Alcea rosea, but a few stand out for their flower color or the cut of their leaves and their resistance to rust. These are the ones worth knowing by name.
Nigra
Its flowers deepen to such a saturated maroon that they read as nearly black against the tall green spike.
Russian hollyhock (Alcea rugosa)
A close relative whose soft yellow flowers set it apart, and it shrugs off hollyhock rust far better than the common kind.
Figleaf hollyhock (Alcea ficifolia)
Its leaves are cut into fig-shaped lobes that give the plant its name, and it stands up to rust better than Alcea rosea.
How to propagate
Raising fresh hollyhocks takes little more than scattered seed, and a settled patch soon renews itself as the dry heads split and spill.
SeedEasy
Sow in late summer (August to September) for bloom the following year, or start indoors in late winter for transplanting after frost. · Germinates in about 1 to 2 weeks; plants form a rosette the first year and bloom the second year.
Seed is the easy path to more hollyhocks. Sow in late summer, around August to September, for flowers the next year, or start the seed indoors in late winter and set the plants out after frost. The seedlings break the surface in 1 to 2 weeks, spread into a low rosette of broad leaves through the first year, and send up their flowering spike in the second. Leave the dry seed heads standing and they scatter and reseed on their own, filling out into standing colonies.
Myths
The hollyhock is a toxic plant, one that dogs and cats must never be allowed near.
The ASPCA lists hollyhock as non-toxic to dogs, cats, and horses, so a nibble in the garden is no cause for alarm. The flowers are safe enough that people eat them. The only real catch is the bristly, hair-covered leaves, which can leave a mild rash on sensitive skin, so wear gloves when you cut the plants.
Hollyhocks behave as sturdy perennials, sending up the same plant from the same root every summer.
Most hollyhocks are biennials, forming a low rosette of broad leaves the first year and then throwing up their flowering spike in the second before they fade. They look permanent only because they self-seed so freely that fresh plants keep filling the same spot year after year.