Ornamental · Asteraceae
Coreopsis
Coreopsis grandiflora
In baking sun and thin, sharp-draining ground, tickseed lines its wiry stems with flat gold daisies from the last weeks of spring until frost.
Full sun
Every 7–14 days
USDA 4–9
1–3 ft · 0.3–0.9 m
Overview
Coreopsis, the perennial known as tickseed, opens flat, daisy-shaped flowers in clear golden-yellow, each a ring of broad ray petals around a darker central disk. It is a member of the daisy family, and in a poor, dry, rocky spot it keeps throwing those bright heads from late spring through the season while pollinators and butterflies work the blooms. The odd name comes from the seeds themselves, small dry flattened things whose shape echoes a tick, not the bug.
Up close the plant reads as wiry and lean rather than lush. Slender stems rise from a low clump and stay tough through drought once established, holding their flowers above leaves that take poor, infertile ground in stride. It keeps blooming from late spring well into summer, often to the first frost, and rich, soggy soil only softens the stems and makes them sprawl, so a spare, dry footing is what keeps the plant crisp.
Two leaf forms set the genus apart at a glance. The large-flowered tickseeds carry big, bold daisy heads on sturdier stems and bloom fast from seed, while the threadleaf types like Moonbeam and Zagreb break their foliage into fine, almost needle-like segments and scatter smaller flowers through that lacy texture over a longer run. Both share the same upright, sun-seeking habit: full light, sharp drainage, and a lean root run.
Care
The short version: full sun and lean, well-drained soil, with water held back until the top half dries out. Feeding stays light, faded flower heads are snipped through the season, and the clump is sheared in midsummer to push a second flush of golden daisies.
Light
Coreopsis reaches toward full sun, and the stems stay upright and the flowers open fullest under it. A little afternoon shade is tolerated, but deeper shade stretches the stems thin and floppy and leaves far fewer of the golden heads.
Water
Once rooted in, the plant runs lean and drought-tough, so the top half of the soil dries out between drinks, roughly every 7 to 14 days. Sharp drainage at the roots counts for more than any fixed schedule. Standing wet softens the crown and is the fastest way to lose it.
Soil
Lean ground keeps the stems firm. It digs into well-drained sandy, rocky, or clay soil and takes poor, infertile spots in stride, rooting happily across a slightly acidic to neutral pH of 5.5 to 7.0. Rich soil only swells soft growth that flops.
Humidity
Plain outdoor air around the foliage is enough, so there is no number to chase. What the plant feels is drainage and airflow at its base, since damp, crowded growth is what lets rot creep into the stems.
Feeding
Feed it rarely, if at all. A light touch through the growing season is plenty, because rich soil pushes soft, leafy growth that crowds out the flowers and weakens the stems.
Pruning
Snip the faded, browning flower heads through the season to keep fresh buds coming. Then shear the whole clump back in mid to late summer to spark a new fall flush and clear out the sprawling, lax foliage.
Size & spacing
The clump stands 1 to 3 feet (30 to 91 cm) tall and fans out about as wide. Set each one 1 to 3 feet (30 to 91 cm) apart so air drifts between the stems and the foliage stays dry.
When to plant
Coreopsis is a hardy perennial for zones 4 through 9. The small dry seed starts indoors a few weeks before the last frost or sows straight into the ground, young plants go out once spring settles, and the golden flowers open 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
Look closely and nearly every coreopsis problem traces to one thing: too much water at the roots. Sharpen the drainage and most of the damage below never marks the leaves or stems. Match what you see on the plant, then act before it spreads.
Dark, water-softened stems at the base and a clump folding over
The stems turn soft and dark right where they meet the soil, and the whole plant tips and folds; this is crown rot, born of waterlogged ground rather than any pest. Once that basal tissue has gone slack and mushy the plant seldom firms up again, so it is lifted out and binned. Watering is cut back, the drainage opened up, and crisp healthy divisions are pressed into ground that drains fast.
Fix:
- Remove and destroy affected plants
- Improve drainage and reduce watering
- Replant healthy divisions in well-drained soil
White lacework at the soil surface and a plant failing fast
Southern blight takes hold in warm, humid air and can drop a plant within days. The tell is a fine white web of fungal threads spun across the soil line, peppered with hard tan beads the size of mustard seeds. The plant is dug out with the soil clinging around it, mulch is drawn back off the stems, and the planting is opened so air can slip through.
Fix:
- Remove and destroy infected plants and surrounding soil
- Avoid mulching directly against stems
- Improve air circulation and drainage
Foliage gnawed into tattered openings, slick trails winding past
The leaves carry torn, irregular holes with frayed edges, the work of slugs and snails that rasp away at the foliage after dark on damp ground. Thin silvery trails dried to a glint trace their path near the wounds. They are picked off by night, the bed is dried out by easing back on water and mulch, and traps or barriers ring the plants they keep returning to.
Fix:
- Hand-pick at night
- Reduce excess moisture and mulch
- Use traps or barriers
Few flowers on floppy, sprawling stems
The stems run long and lax, leaning out over the bed in a tangle of leaf with only a scattering of flowers; the root of it is soil that is too rich or too moist, and old faded blooms left in place drag it down further. The plant is shifted into full sun and lean, well-drained ground and fed sparingly. Spent flowers are snipped through the season, and the whole clump is sheared back hard in mid to late summer to push out a fresh set.
Fix:
- Deadhead regularly
- Shear back in mid to late summer
- Reduce fertilizer and grow in full sun and leaner soil
Toxicity
Reassuring news for a home with animals. Coreopsis is non-toxic to cats, dogs, and horses on the ASPCA's list, and neither its golden flowers nor its lean foliage poses any known threat to other animals or people. A nibbled leaf or petal is nothing to worry about.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are safe with it. The ASPCA lists coreopsis as non-toxic, so a cat that tears off a petal or leaf comes to no harm.
Dogs None
Dogs are safe too. The plant holds no known toxins, though a dog that gulps down a mouthful of leaves and stems may get a brief, harmless upset stomach.
Horses None
Horses are safe near it. Coreopsis is listed non-toxic, so the foliage poses no poisoning risk where they graze.
Rabbits Safe
Rabbits are safe with it. A nibbled petal or leaf carries nothing that can harm them.
Livestock Safe
Cattle, goats, and sheep can crop the foliage nearby without any toxicity risk.
Birds Safe
Birds come to no harm from it, and many pick at the dry, bristly seed heads for food.
People Safe
It is non-toxic to people. The plant is grown for its flowers rather than as a crop, so it offers no edible part.
Varieties
Coreopsis comes in dozens of named selections that differ most in leaf cut and flower size. A few turn up again and again, and these are the ones worth knowing by sight and name.
Coreopsis verticillata 'Moonbeam'
A threadleaf type whose foliage is cut into fine, needle-thin segments, scattered over with soft, pale yellow flowers across a long season.
Coreopsis verticillata 'Zagreb'
A compact threadleaf selection that builds a low, dense mound of fine foliage studded with deep golden-yellow flowers.
Coreopsis verticillata 'Grandiflora'
A more compact threadleaf form rising to about 2.5 feet, its fine leaves topped by bright golden-yellow daisy heads.
Coreopsis grandiflora 'Early Sunrise'
A large-flowered tickseed bearing full, semi-double golden blooms packed with ray petals, opening fast from seed in its first year.
How to propagate
Coreopsis multiplies with ease, whether the clump is split apart or the small dry seed is sown, and the plant often scatters its own seed before you reach for the trowel.
DivisionEasy
Early spring; divide clumps every 2 to 3 years to maintain vigor · One growing season
Division keeps the clump full and vigorous. In early spring the crown is lifted whole and teased apart into firm, well-rooted pieces, then replanted to refresh worn-out growth and hold the spreading clump in bounds. The fresh divisions knit 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
The small dry seeds sprout readily, started indoors 6 to 8 weeks before the last frost or scattered straight onto the bed. Many large-flowered types push up flowers in their first year. Large-flowered tickseed is often short-lived, yet it sheds seed so freely that fresh seedlings fill the gaps and the patch carries on.
Myths
Tickseed is named because the plant attracts or harbors ticks.
The name describes the seeds, not the bugs. Each one is a small, dry, flattened seed whose shape and dark markings mimic a tick, and that close likeness is all there is to it. In flower it draws pollinators and butterflies, never ticks.
Coreopsis counts as a poisonous plant, so dogs and cats have to be kept out of its reach.
The ASPCA lists coreopsis as non-toxic to dogs, cats, and horses. A pet that bites into a leaf or flower is in no danger.