Ornamental · Asteraceae
Coreopsis
Coreopsis grandiflora
Give it full sun and lean, dry soil, and tickseed throws gold daisies from late spring to frost.
Full sun
Every 7–14 days
USDA 4–9
1–3 ft · 0.3–0.9 m
Overview
Coreopsis, better known as tickseed, is one of the easiest perennials a sunny garden can hold. It belongs to the daisy family and answers a poor, dry, rocky spot with a long run of golden-yellow flowers that pollinators and butterflies work all season. The odd name has nothing to do with the bug; it comes from the small dry seeds, which look like ticks up close.
What sets coreopsis apart is how little it asks. It shrugs off drought once established, takes lean infertile ground in stride, and keeps blooming from late spring well into summer, often to the first frost. Rich soil and heavy watering work against it, so the usual gardener's instinct to pamper a plant is exactly the wrong move here.
The genus splits into two camps worth knowing. The large-flowered tickseeds carry big bold daisies and bloom fast from seed, while the threadleaf types like Moonbeam and Zagreb trade size for a haze of fine foliage and smaller flowers held over a longer window. Both want the same thing: sun, sharp drainage, and a light hand.
Care
The short version: full sun and lean, well-drained soil, with water only when the top half dries out. Skip the heavy feeding, deadhead through the season, and shear the clump back in midsummer for a second flush.
Light
Coreopsis wants full sun and flowers best with it. It will take a little afternoon shade, but anything more leaves you with floppy, leggy stems and far fewer blooms.
Water
This is a drought-tolerant plant once it settles in, so let the top half of the soil dry out between drinks, roughly every 7 to 14 days. Sharp drainage matters more than any schedule. The fastest way to kill coreopsis is to keep it wet.
Soil
Lean is the goal. It thrives in well-drained sandy, rocky, or clay ground and even tolerates poor, infertile spots, holding a slightly acidic to neutral pH of 5.5 to 7.0. Rich soil only makes it flop.
Humidity
Ordinary outdoor air suits it, so there's no number to chase. What counts is drainage and airflow, since damp, crowded conditions are what invite rot.
Feeding
Feed it rarely, if at all. A light touch during the growing season is plenty, because rich soil pushes soft, floppy growth at the expense of flowers.
Pruning
Deadhead spent blooms through the season to keep more coming. Then shear the whole clump back in mid to late summer to spark a fresh fall flush and tidy up any sprawling foliage.
Size & spacing
Plants run 1 to 3 feet (30 to 91 cm) tall and spread about as wide. Give each one 1 to 3 feet (30 to 91 cm) of room so air moves freely through the clump.
When to plant
Coreopsis is a hardy perennial built for zones 4 through 9. Start seed indoors a few weeks before the last frost or sow it straight in the ground, set plants out once spring has settled, and the flowers follow from late spring into summer.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6 to 8 weeks before last spring frost
- Plant: After last spring frost in spring
- Harvest: Late spring to late summer, sometimes to first frost
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Almost every problem with coreopsis traces back to one thing: too much water. Get the drainage right and most of the trouble below never starts. Match what you see, then act before it spreads.
Mushy stems at the soil line and a plant that flops over
This is crown rot, and it comes from soil that stays too wet rather than from any pest. Once the tissue at the base turns soft and dark, the plant rarely recovers, so pull it and bin it. Cut your watering back, improve the drainage, and set healthy divisions in ground that drains fast.
Fix:
- Remove and destroy affected plants
- Improve drainage and reduce watering
- Replant healthy divisions in well-drained soil
White fungal threads at the base with sudden collapse
Southern blight strikes in warm, humid weather and can kill a plant fast. The giveaway is a mat of white fungal threads at the soil line dotted with tan, mustard-seed-sized sclerotia. Dig out the plant along with the soil around it, keep mulch off the stems, and open things up so air can move.
Fix:
- Remove and destroy infected plants and surrounding soil
- Avoid mulching directly against stems
- Improve air circulation and drainage
Ragged holes chewed in the leaves with slime trails
Slugs and snails chew these ragged holes, working mostly at night when the ground is damp. The silvery trails near the damage give them away. Pick them off after dark, dry things out by easing back on water and mulch, and ring vulnerable plants with traps or barriers.
Fix:
- Hand-pick at night
- Reduce excess moisture and mulch
- Use traps or barriers
Few flowers on floppy, sprawling stems
When coreopsis grows lush and leggy with little to show for it, the cause is usually soil that is too rich or too moist, made worse by leaving old flowers on the plant. Move it into full sun and lean, well-drained ground, and go light on the feeding. Deadhead through the season and shear the whole clump back in mid to late summer to bring on fresh bloom.
Fix:
- Deadhead regularly
- Shear back in mid to late summer
- Reduce fertilizer and grow in full sun and leaner soil
Toxicity
Good news for households with animals. Coreopsis is non-toxic to cats, dogs, and horses on the ASPCA's list, and it poses no known threat to other animals or people. A nibbled leaf or flower is nothing to worry about.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe around cats. The ASPCA lists coreopsis as non-toxic, so a curious nibble is nothing to worry about.
Dogs None
No concern for dogs. It carries no known toxins, though wolfing down a lot of any plant can still leave a dog with a passing upset stomach.
Horses None
Listed as non-toxic to horses, so it poses no poisoning risk where they graze.
Rabbits Safe
Fine for rabbits. The leaves and flowers hold nothing harmful if one gets browsed.
Livestock Safe
Cattle, goats, and sheep can graze near it without any toxicity concern.
Birds Safe
Harmless to birds, which often seek out the dried seed heads as food.
People Safe
No toxicity to people. It is grown as a garden flower, not a food crop, so there is no edible part to harvest.
Varieties
Coreopsis comes in dozens of named selections, but a few turn up again and again for good reason. These are the ones worth knowing by name.
Coreopsis verticillata 'Moonbeam'
A threadleaf type whose finely cut foliage carries soft, pale yellow flowers over a long season.
Coreopsis verticillata 'Zagreb'
A compact threadleaf selection that holds a tidy, mounding shape under golden-yellow flowers.
Coreopsis verticillata 'Grandiflora'
A more compact threadleaf form reaching about 2.5 feet, topped with bright golden-yellow daisies.
Coreopsis grandiflora 'Early Sunrise'
A large-flowered tickseed with semi-double golden blooms that flowers fast from seed in its first year.
How to propagate
Coreopsis is simple to multiply, whether you split an existing clump or grow it from seed, and the plant often reseeds itself before you get the chance.
DivisionEasy
Early spring; divide clumps every 2 to 3 years to maintain vigor · One growing season
Dividing is the surest way to keep coreopsis vigorous. Lift an established clump in early spring, split it into healthy sections, and replant them to renew tired plants and keep their spread in check. The divisions settle in over a single growing season.
SeedEasy
Start indoors 6 to 8 weeks before last frost or direct sow; self-seeds readily · Blooms first year for many large-flowered types
Coreopsis grows easily from seed, started indoors 6 to 8 weeks before the last frost or sown straight into the bed. Many large-flowered types flower in their first year. Large-flowered tickseed can be short-lived, but it reseeds itself so freely that the patch tends to carry on without help.
Myths
Tickseed gets its name because the plant attracts or harbors ticks.
The name points at the seeds, not the bugs. Each small dry seed looks like a tick, and that resemblance is the whole story. The plant draws pollinators and butterflies, not ticks.
Coreopsis is poisonous and should be kept away from cats and dogs.
The ASPCA lists coreopsis as non-toxic to dogs, cats, and horses. A pet that nibbles a leaf or flower is in no danger.