Ornamental · Asteraceae
Calendula
Calendula officinalis
Give it full sun and lean soil, and pot marigold keeps blooming from spring right up to frost.
Full sun
Every 3–7 days
39–75°F · 4–24°C
45–65 days
Overview
Calendula, or pot marigold, is a cool-season annual in the daisy family, and honestly it's one of the most easygoing flowers around. Sow it once and it blooms from spring into fall, then drops seed and pops back up on its own next year. The bright yellow and orange heads are edible, too, which is why cooks have been tossing the petals into salads and using them to color food for ages.
Here's the nice part: it barely asks for anything. Give it average, well-drained soil and a spot in full sun, and it actually blooms better when you skip the fertilizer. Sure, it runs out of gas in real summer heat, but cut it back hard and it'll often come back with a fresh round of flowers once fall cools things down.
So if you're new to this or just busy, calendula's a safe bet. Deadhead it here and there, keep the leaves dry so mildew stays away, and it'll hold the front of a bed or a kitchen border with hardly any fuss at all.
Care
The short version: full sun, plain well-drained soil, and an easy hand with the fertilizer. Keep it watered evenly at the base, snip off the dead flowers, and it'll bloom cool-season from spring through fall.
Light
Calendula flowers best in full sun, but it'll take partial shade, which really helps where summers get hot. More sun just means more blooms, so give it the brightest spot you've got.
Water
Keep the soil evenly moist with regular watering, and make sure it drains so the roots aren't sitting wet. Water down at the base instead of over the top, since wet leaves are an open invitation for powdery mildew. Overall, it's only a medium drinker.
Soil
Average, well-drained soil is all it really wants, and it doesn't care whether that's clay, loam, sand, or rich ground. Any pH from 5.5 to 7.0 works fine. Good drainage matters way more here than how rich the soil is.
Temperature
This one's a cool-weather plant, happiest around 39°F to 75°F (4°C to 24°C). It can stall and look rough in midsummer heat, but it usually perks right back up once fall cools off.
Humidity
Regular outdoor humidity is no problem, so there's no number to worry about. Moving air matters more than the reading, since it's the crowded, damp plants that end up with mildew.
Feeding
Feed it lightly during the growing season, or not at all. Calendula blooms best on lean soil, and a heavy feed just grows leaves instead of flowers.
Pruning
Deadhead the spent blooms as they fade and you'll keep new ones coming while cutting down on self-seeding. If it flags in summer heat, cut it back hard and it'll often rebloom once fall shows up.
Size & spacing
Plants get to about 12 to 24 inches (30 to 61 cm) tall and spread out about the same. Give each one that much space so air moves freely and mildew has a harder time getting going.
When to plant
Calendula does its best in the mild stretches at either end of summer, so timing's easy to get right. Start seed indoors in late winter or just sow it into the ground around the last frost, and it'll flower from spring until a hard frost finally shuts it down.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: About 6 to 8 weeks before the last spring frost
- Plant: Direct sow or transplant just before to around the last spring frost; a cool-season annual best in spring and fall
- Harvest: Blooms spring through summer, continuing almost nonstop until first heavy frost in cool climates
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Calendula's tough, and most of what bugs it shows up right on the leaves or new growth. Catch it early and a quick fix usually handles it. Find what matches below, then deal with it before it spreads.
Streaky, warped leaves and growth that's going nowhere
When the leaves go blotchy yellow-green and twisty and nothing you do helps, that usually means cucumber mosaic virus, which aphids carry around from plant to plant. There's no cure, so the kindest move is to dig out and toss any plant that's got it before it spreads. Keep the aphids down and wash your hands between plants, and you'll slow it way down.
Fix:
- Remove and destroy infected plants to limit spread
- Control aphid vectors
- Avoid handling healthy plants after touching infected ones
Leaves that look like they've been dusted with flour
See a chalky white dust on the leaves? That's powdery mildew, a fungus that loves crowded plants stuck in still, muggy air. The cure's pretty simple: thin things out so air can move, water down low so the leaves stay dry, and snip off any leaf that's really caked. Once it's in full sun with a little breathing room, it usually stays gone.
Fix:
- Improve air circulation by thinning and spacing plants
- Water at the base to keep foliage dry
- Remove and discard severely affected leaves
Little bugs bunching up on fresh shoots and leaving stickiness behind
Those tiny green or black specks crowding the new shoots and buds are aphids, and they go straight for the softest growth. A good blast from the hose knocks most of them loose, and insecticidal soap sorts out a bigger crowd. Ease up on the high-nitrogen feeding that grows the soft, sappy shoots they love, and let the lady beetles help out too.
Fix:
- Spray plants with a strong stream of water to dislodge aphids
- Apply insecticidal soap if populations are high
- Encourage beneficial insects such as lady beetles
Chewed-up gaps showing up overnight in foliage and blooms
Torn-up holes and a shiny trail? That's slugs and snails, and they come out after dark to hit the young plants first. Grab a flashlight at dusk and pick them off, then clear out the damp junk they hide under during the day. If they keep coming, iron-phosphate baits or a simple trap will do the trick.
Fix:
- Hand-pick slugs and snails in the evening
- Remove garden debris that provides shelter
- Use traps or iron-phosphate baits if damage is heavy
Toxicity
Good news on this front. The ASPCA lists pot marigold as non-toxic to cats, dogs, and horses, and the petals are edible for people too. A grazing pet or a curious kid? No danger here, so go ahead and plant it anywhere in the garden.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
No worries about the cat here. The ASPCA has pot marigold down as non-toxic to cats, so a nibble's totally fine.
Dogs None
Dogs are good too. This is the garden pot marigold, not the bedding kind, and the ASPCA calls it safe.
Horses Safe
Calendula doesn't have any known toxic compounds, so a horse grazing on it has nothing to worry about.
Rabbits Safe
Rabbits can munch the leaves and petals just fine, and the flowers often get grown as safe forage.
Livestock Safe
Cattle, goats, and sheep do fine with calendula, and there aren't any reports of it poisoning them.
Birds Safe
Backyard birds can pick at the seed heads and petals without any problem.
People Safe
The petals are edible and show up in salads or as a saffron-style coloring, so people are in the clear too.
Varieties
Calendula comes in a few flower forms and colors worth a quick look before you sow. Here are the ones you'll bump into most.
Double-flowered types
These have full, many-petaled heads in yellows through deep orange, so they look a lot plusher than the plain single daisy.
Single-flowered types
These keep it simple with one ring of ray petals around a flat little center, the classic open daisy look.
Yellow to orange color forms
These run anywhere from bright yellow to deep orange, and since the petals are edible they make an easy garnish or natural dye.
How to propagate
Calendula grows from seed and not much else, but it pretty much handles that itself, sprouting fast and even reseeding for next year.
SeedEasy
Start indoors about 6 to 8 weeks before the last frost, or direct sow outdoors around the last spring frost · Germinates in about 5 to 15 days; first blooms in roughly 45 to 65 days from seed
Want an easy one to grow from seed? Calendula's about as forgiving as they come. Start it indoors 6 to 8 weeks before your last frost, or just poke the seed into the ground around frost at 1/4 to 1/2 inch deep. You'll see sprouts in 5 to 15 days and the first flowers in 45 to 65 days. Leave it alone and it drops its own seed for next year, but never so much that it takes over.
Myths
Calendula and those classic bedding marigolds are one and the same flower, and they'll make a pet a bit sick.
It's an easy mix-up, but pot marigold is Calendula officinalis, a whole different genus from the Tagetes bedding marigolds. The ASPCA lists it as non-toxic to dogs and cats, so that toxicity worry just doesn't apply here.
Calendula won't put on a decent flower show unless the soil is rich and it gets fed generously.
Nope, it does great in plain, well-drained ground and barely asks for anything. Heavy feeding actually works against the flowers, growing leaves instead of blooms, so go easy on the fertilizer.