Ornamental · Malvaceae
Hollyhock
Alcea rosea
Tall, old-fashioned spires of bloom that plant themselves once you let them go to seed.
Full sun
Every 5–7 days
USDA 3–9
5–8 ft · 1.5–2.4 m
Overview
Hollyhocks are the cottage-garden classic, the kind that sends flower spikes shooting past 8 feet (244 cm) to line a fence or a back wall with summer color. They're part of the mallow family and have been a dooryard favorite for generations. Ever noticed how those saucer-shaped blooms just climb straight up one tall stalk? That's them, going strong from June through August.
You might think something this tall would be a handful, but they're actually easy to grow. Most are biennials, so a plant spends its first year as a low rosette of leaves and saves the flowering for year two. They make up for the slow start by self-seeding like mad, so once you've got a stand going, it tends to keep itself going.
The one thing you'll end up managing is rust, a leaf fungus that tags along with hollyhocks almost everywhere. Give them full sun, a bit of room for air to move, and water at the roots instead of over the top, and you'll keep the worst of it down while the flowers do their thing.
Care
The short version: give hollyhocks full sun and rich, well-drained soil, keep them evenly moist by watering at the base, and space them out so air can move and rust stays down.
Light
Give them full sun and they'll flower their best and stand up straight instead of flopping. They'll take a bit of partial shade if they have to, but where it's too shady the stalks stretch, lean over, and don't bloom much.
Water
Go for average, even moisture rather than letting the soil bounce from soaked to bone dry. Water at the base with a soaker hose or drip line so the leaves stay dry, and honestly that's one of the best things you can do to slow rust down. Just don't let them sit in wet, soggy soil over winter.
Soil
Plant them in average, rich, well-drained loam with some compost mixed in. They're not picky about pH and do fine anywhere from 6.0 to 8.0, so good drainage matters way more than the exact number.
Humidity
Regular outdoor humidity is plenty, so there's no number to worry about. What really matters is airflow, because still, damp air around crowded leaves is exactly what rust wants.
Feeding
One feed in spring is all they need. Mix in compost or a balanced general-purpose fertilizer as growth kicks off, and they'll carry themselves the rest of the season.
Pruning
Cut the spent flower spikes to tidy things up or to keep the self-seeding in check if it's spreading more than you'd like. And just as important, strip off and toss any rust-spotted lower leaves, then clear out all the old debris in fall so the fungus can't overwinter.
Size & spacing
These get tall, running 5 to 8 feet (152 to 244 cm) high but staying skinny at 12 to 24 inches (30 to 61 cm) wide. Give each one that full width of room so air moves freely between them and rust has a tougher time spreading.
When to plant
Hollyhocks work on a two-year clock, so a little patience helps. Sow the seed in late summer or start it indoors in late winter, put the young plants out after the last spring frost, and the flowers show up from June through August 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
Just about every hollyhock problem lands on the leaves, and rust is the one you'll bump into first. Find what you're seeing below, then jump on it early, because most of these are a lot easier to stop than to fix once they've spread.
Orange spots on top, rusty bumps underneath
See yellow-orange spots up top with raised rusty bumps right under them? That's hollyhock rust, and honestly it follows this plant just about everywhere. The badly hit leaves end up holey and shriveled, so don't wait around. Pick off the marked leaves as soon as they show, water at the base so the foliage stays dry, and rake up every scrap in fall so the spores can't ride out the winter.
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 chewed down to lace
If the leaves look like lace, you've got one of two culprits. Japanese beetles show up in daytime groups and leave nothing but the veins, while slugs do their damage at night and give themselves away with slime trails. For the beetles, just flick them into soapy water first thing in the morning. For slugs, set out some baits or traps wherever they're a problem.
Fix:
- Hand-pick beetles into soapy water in early morning
- Reduce nearby turf grub habitat
- Use slug baits or traps where slugs are present
Not many blooms and pinholes in the buds
Fewer flowers than expected? That's usually the hollyhock weevil, a little black bug with tan legs and a long snout that hangs out on the buds and open blooms. It drills into the buds and seeds, which quietly cuts down the flowering. Just tap the weevils onto a sheet and get rid of them, then clear off the old seed heads where the babies 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 with dark blotches
Leaf spot and anthracnose fungi like to move into the lower leaves when plants are crowded, stressed, or getting wet from overhead watering, though the flowers usually stay clean. It looks pretty rough, but it hardly ever does real damage. Pull off the worst leaves, open up the spacing so air can move, and water at the base instead of over the top.
Fix:
- Remove affected leaves
- Improve air circulation
- Water at the base rather than overhead
Toxicity
Good news if you've got pets: the ASPCA lists hollyhock as non-toxic to cats, dogs, and horses, and the flowers are safe enough that people eat them. The only thing to keep an eye on is the bristly leaves and fibers, which can leave a mild skin rash on sensitive people, so it's smart to pull on gloves before you handle or cut the plants.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
No need to fuss over the cat here. The ASPCA has hollyhock down as non-toxic to cats, so a curious nibble won't poison one. Sure, a cat that stuffs itself on any plant might bring a bit back up, but there's nothing dangerous about it.
Dogs None
Dogs are fine around it too. Hollyhock is non-toxic to dogs, and about the worst a leaf-munching pup gets is a quick, mild bit of tummy trouble from all the roughage.
Horses None
Horses? No problem at all. They can graze near hollyhocks all they like, because the plant's got no toxic principles for them.
Rabbits Safe
Rabbits can tuck into the leaves and flowers with no trouble, since these mallow-family plants don't carry anything that would hurt them.
Livestock Safe
Cattle, goats, and sheep won't run into any toxic risk from hollyhock if they browse a plant along the pasture or garden edge.
Birds Safe
Backyard birds and poultry can peck away at the foliage and seeds without it hurting them a bit.
People Safe
It's safe for people too, and here's a fun bit: the flowers are actually edible, and they turn up as a garnish or steeped into tea. The only thing to watch is those bristly leaves and fibers, which can leave a mild skin rash on sensitive folks, so it's a good idea to throw on gloves when you handle or cut the plants.
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 plain old Alcea rosea, but a few really stand out, whether it's for their color or the way they shrug off rust. These are the ones worth knowing by name.
Nigra
Its flowers are such a deep maroon that they read as nearly black next to the green spike.
Russian hollyhock (Alcea rugosa)
It's a close relative with soft yellow flowers, and it shakes off hollyhock rust way better than the common kind does.
Figleaf hollyhock (Alcea ficifolia)
It gets its name from those fig-shaped leaves, and it holds up against rust better than Alcea rosea too.
How to propagate
Hollyhocks are dead simple from seed, and once a stand gets going it pretty much sows itself.
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.
Want more hollyhocks? Seed is the easy way to go. Sow in late summer, around August to September, for flowers the next year, or start them indoors in late winter and pop the plants out after frost. The seedlings come up in 1 to 2 weeks, hang out as a low rosette their first year, and bloom in the second. And if you leave the seed heads alone, they'll reseed themselves and settle into standing colonies over time.
Myths
Hollyhocks are poisonous, so keep them away from dogs and cats.
You can let that one go. The ASPCA lists hollyhock as non-toxic to dogs, cats, and horses, so a nibble out in the garden is no big deal. The flowers are safe enough that people eat them. The only real thing to watch is the bristly leaves, which can leave a mild rash on sensitive skin, so wear gloves when you cut the plants.
Hollyhocks are reliable, long-lived perennials.
Here's the surprise: most hollyhocks are actually biennials. They grow a leafy rosette the first year, flower the second, and then they fade out. They only seem permanent because they self-seed like crazy, so new plants keep popping up and filling the same spot year after year.