Ornamental · Asteraceae
Calendula
Calendula officinalis
Give it full sun and lean soil and pot marigold rewards you with bloom from spring all the way to frost.
Full sun
Every 3–7 days
39–75°F · 4–24°C
45–65 days
Overview
Calendula, fondly known as pot marigold, is a cool-season annual in the daisy family, and it is one of the most willing flowers a new gardener can grow. Sow it just once and it blooms from spring into fall, then drops its own seed and comes back next year with no help from you. The warm yellow and orange heads are edible, which is why cooks have long sprinkled the petals into salads and used them to tint food a sunny gold.
Best of all, it asks for so little. A spot in full sun and ordinary well-drained soil will do, and it genuinely flowers better when you resist the urge to fertilize. It can lose steam in true summer heat, but do not give up on it, because a brave cutback usually coaxes a fresh wave of flowers once cooler fall weather returns.
If you are just starting out or simply short on time, calendula is a kind plant to lean on. A bit of deadheading here and there, dry foliage to keep mildew away, and it will carry the front of a bed or a kitchen border beautifully, forgiving the odd mistake along the way.
Care
The short version: full sun, plain well-drained soil, and a light hand with fertilizer are all it needs. Keep it evenly watered at the base, snip off the spent flowers, and this cheerful cool-season bloomer carries you from spring through fall.
Light
Calendula is happiest and flowers most freely in full sun, though it will accept partial shade, which can be a real kindness where summers run hot. As a rule, the more sun it soaks up, the more bloom you get, so offer it the brightest spot you have.
Water
Aim to keep the soil evenly moist with steady watering, and make sure it drains well so the roots are never left sitting wet. Water down at the base instead of over the top, since damp leaves are an open door to powdery mildew. Its thirst is only medium overall, so there is no need to fuss.
Soil
Plain, well-drained soil is genuinely all it wants, and it takes clay, loam, sand, or richer ground in stride. Any pH from 5.5 to 7.0 suits it nicely. Good drainage matters far more here than how rich the soil is.
Temperature
This is a cool-weather plant at heart, most content somewhere around 39°F to 75°F (4°C to 24°C). It may stall and look a little tired in the heat of midsummer, but it tends to perk right back up as fall cools things off.
Humidity
Everyday outdoor humidity is no bother at all, so there is no number to chase. Moving air matters more than the reading, because it is the crowded, soggy plants that tend to catch mildew.
Feeding
Feed lightly, if you feed it at all, through the growing season. Calendula blooms best on lean soil, and a heavy hand with fertilizer simply grows leaves where you were hoping for flowers.
Pruning
Deadhead the spent blooms as they fade and you will keep fresh ones coming while gently curbing self-seeding. Should the plant flag in summer heat, do not hesitate to cut it back hard, as it often rewards you with a rebloom once fall arrives.
Size & spacing
Plants grow to about 12 to 24 inches (30 to 61 cm) tall and spread out to a similar width. Give each one that much elbow room so air can move freely and mildew finds far less of a foothold.
When to plant
Calendula loves the mild weather at either end of summer, so timing is on your side. Start seed indoors in late winter or simply sow it into the ground around the last frost, and the flowers will keep coming from spring right up until a hard frost finally calls a halt.
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 is a hardy, good-natured plant, and most of what troubles it shows up plainly on the leaves or new growth. Spot it early and a simple step usually puts things right. Find what matches your plant below, then act before it has a chance to spread.
Twisted, blotchy leaves on a plant that has lost its vigor
When leaves turn blotchy yellow-green and twisted and neither water nor feeding brings them back, the cause is likely cucumber mosaic virus, which aphids pass from one plant to the next. This one cannot be cured, so it is kindest to the rest of your garden to dig out and dispose of any affected plant before it spreads. Keeping aphids down and rinsing your hands between plants slows the virus, and the rest of your calendula will be fine.
Fix:
- Remove and destroy infected plants to limit spread
- Control aphid vectors
- Avoid handling healthy plants after touching infected ones
A dusty white film spreading across leaves and stems
If a pale, flour-like dust is settling over the foliage, you are looking at powdery mildew, a fungus that moves in when plants are packed close together in stale, damp air. The fix is gentle and forgiving: open the planting up so a breeze can pass through, water down at the soil so leaves stay dry, and gently remove any leaf that is heavily coated. A sunny spot with breathing room keeps it from returning.
Fix:
- Improve air circulation by thinning and spacing plants
- Water at the base to keep foliage dry
- Remove and discard severely affected leaves
Tiny soft insects gathering on fresh buds and shoots
Those little green or black dots clustered on the newest growth and flower buds are aphids, and they are nothing to panic over. A firm spray from the hose washes most of them away, and a little insecticidal soap takes care of a bigger crowd. Go easy on the high-nitrogen feeding that grows the soft, juicy shoots they crave, and the lady beetles in your garden will happily pitch in 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
Torn holes appearing in young leaves and flowers overnight
Ragged holes and a faint shiny trail across the foliage are the work of slugs and snails, which come out after dark and favor your youngest plants. Take a flashlight out at dusk and pick them off by hand, and tidy away the damp leaf litter where they shelter during the day. If they keep at it, an iron-phosphate bait or a simple trap will turn the tide for you.
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
Here is some lovely news. The ASPCA lists pot marigold as non-toxic to cats, dogs, and horses, and the petals are even edible for people. A grazing pet or a curious little one is in no danger here, so you can plant it freely anywhere in the garden and rest easy.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
You can relax around the cat. The ASPCA lists pot marigold as non-toxic to cats, so a curious nibble will cause no harm at all.
Dogs None
Dogs are perfectly safe with this one too. It is the garden pot marigold rather than the bedding kind, and the ASPCA rates it as safe.
Horses Safe
There are no known toxic compounds in calendula, so you need not worry about a grazing horse coming to any harm.
Rabbits Safe
Rabbits are welcome to browse the leaves and petals, and the cheerful flowers are often grown as safe forage.
Livestock Safe
Cattle, goats, and sheep handle calendula just fine, with no reports of poisoning to worry about.
Birds Safe
Backyard birds can peck happily at the seed heads and petals with nothing to fear.
People Safe
The petals are edible and lovely scattered through salads or used as a saffron-style coloring, so there is nothing for people to watch out for.
Varieties
Calendula comes in a few flower forms and colors that are nice to know before you sow. These are the ones you are most likely to come across.
Double-flowered types
You will know these by their full, many-petaled heads in warm yellows through deep orange, rounder and plusher than the simple open daisy.
Single-flowered types
These show off open, daisy-style blooms, just one ring of ray petals framing a flat button of a center.
Yellow to orange color forms
Their flowers glow anywhere from sunny yellow to rich orange, and because the petals are edible they make a friendly garnish or a gentle natural dye.
How to propagate
Calendula grows from seed and almost nothing else, but it does so with hardly any effort on your part, sprouting quickly and even reseeding itself to greet you again 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
Few flowers are as forgiving to start from seed as calendula, so this is a wonderful one to learn on. Sow indoors 6 to 8 weeks before your last frost, or press the seed straight into the ground around frost at about 1/4 to 1/2 inch deep. Green sprouts push up in 5 to 15 days and the first flowers open within 45 to 65 days. Leave it be and the plant quietly drops seed to return next year, never so much that it overruns the bed.
Myths
Calendula is just another name for the common bedding marigold and is mildly toxic to pets.
It is easy to mix them up, but pot marigold is Calendula officinalis, a separate genus from the Tagetes bedding marigolds. The ASPCA lists it as non-toxic to dogs and cats, so you can set that worry aside entirely.
Calendula needs rich soil and heavy feeding to bloom well.
Happily, the opposite is true, and it thrives in plain, well-drained ground while asking for almost nothing. Heavy feeding actually works against the flowers, growing leaves where you wanted blooms, so a light touch with fertilizer is all you need.