Large-Flowered Tickseed

Coreopsis grandiflora

Large-Flowered Tickseed (Coreopsis grandiflora) is a perennial native wildflower. Hardy in USDA zones 4 to 9.

Sun

Partial shade

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Zones

4–9

USDA hardiness

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Height

1-3 feet

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Planting Timeline

Zone:

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Transplant

Direct Sow

Transplant

Direct Sow

Showing dates for Large-Flowered Tickseed in USDA Zone 7

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Zone Map

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Large-Flowered Tickseed · Zones 4–9

What grows well in Zone 7? →

Growing Details

Difficulty

Easy

Spacing12-18 inches

SoilWell-drained soil, tolerates poor to average fertility, prefers slightly acidic to neutral pH

pHAcid ( 6.0), Neutral (6.0-8.0)

WaterDrought tolerant

SeasonPerennial

ColorGolden yellow

Zone-by-Zone Planting Calendar

Zone	Indoor Start	Transplant	Direct Sow	Harvest
Zone 4	—	June – July	April – June	—
Zone 5	—	May – July	April – June	—
Zone 6	—	May – July	April – June	—
Zone 7	—	May – June	March – May	—
Zone 8	—	April – June	March – May	—
Zone 9	—	March – May	February – April	—

Complete Growing Guide

Light: Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: Clay, Sand, Shallow Rocky. Soil pH: Acid (<6.0), Neutral (6.0-8.0). Drainage: Good Drainage, Occasionally Dry. Height: 1 ft. 0 in. - 3 ft. 0 in.. Spread: 1 ft. 0 in. - 3 ft. 0 in.. Spacing: 12 inches-3 feet. Growth rate: Medium. Maintenance: Medium. Propagation: Division, Seed. Regions: Coastal, Mountains, Piedmont.

Harvesting

The achenes are flat and oblong.

Type: Achene.

Harvest time: Summer

Storage & Preservation

Large-Flowered Tickseed flowers are best enjoyed fresh and should be placed in a cool location away from direct heat and ripening fruit, ideally in a vase with fresh water at room temperature (65-70°F) with moderate humidity. Cut flowers typically last 7-10 days. For preservation, dry flowers by hanging bundles upside-down in a warm, well-ventilated area for 2-3 weeks—they retain color beautifully and last indefinitely. Alternatively, press flowers between parchment paper under weight for 2-4 weeks for crafts or arrangements. For seed saving, allow spent flowers to dry on the plant, then collect seed heads in fall for next year's planting.

History & Origin

Origin: Canada, U.S.A., NC

Advantages

+Produces abundant golden-yellow flowers from summer through fall consistently
+Thrives in poor, sandy soils where many plants struggle or fail
+Requires minimal water once established, making it drought-tolerant
+Hardy across zones 4-9 with excellent cold and heat tolerance
+Attracts pollinators while remaining deer and rabbit resistant

Considerations

-Short-lived perennial often declining after 2-3 years without deadheading
-Prone to root rot and fungal issues in wet, poorly-drained soils
-Self-seeds aggressively, potentially becoming weedy in cultivated gardens

Companion Plants

The native prairie companions in this plant's beneficial list — Purple Coneflower (Echinacea purpurea), Black-Eyed Susan (Rudbeckia hirta), Wild Bergamot (Monarda fistulosa), and Little Bluestem Grass (Schizachyrium scoparium) — share the same basic needs as Coreopsis: lean soil, good drainage, and full to partial sun. Little Bluestem is a particularly good structural partner because its deep fibrous roots pull from a different zone than Coreopsis's shallow root system, so the two sidestep most competition for water and nutrients. Yarrow and Butterfly Weed (Asclepias tuberosa) fill out the pollinator draw without muscling in on space.

The harmful companions are a different story. Black Walnut (Juglans nigra) produces juglone, a root-exuded compound that moves through soil and suppresses susceptible plants — and Coreopsis falls in that category. Tree of Heaven (Ailanthus altissima) and Crown Vetch (Coronilla varia) are both prolific spreaders; either one can shade out a Coreopsis planting within a season or two if they get a foothold nearby. Give all three a wide berth.

Plant Together

Purple Coneflower

Similar growing conditions, attracts beneficial pollinators and creates complementary bloom succession

Black-Eyed Susan

Compatible native wildflower with similar water and soil needs, extends flowering season

Wild Bergamot

Attracts beneficial insects and pollinators, helps deter harmful pests through aromatic oils

Little Bluestem Grass

Provides structural support and winter interest, compatible prairie companion with similar drought tolerance

New England Aster

Late-season bloomer that extends pollinator resources, similar soil and sun requirements

Yarrow

Attracts beneficial predatory insects, improves soil through deep taproot

Prairie Dropseed

Native grass companion that provides contrast and doesn't compete for resources

Butterfly Weed

Attracts butterflies and beneficial insects, complementary root systems and bloom times

Keep Apart

Black Walnut

Produces juglone toxin that inhibits growth of many wildflowers including tickseed

Tree of Heaven

Aggressive invasive that releases allelopathic chemicals suppressing native wildflower growth

Crown Vetch

Invasive legume that forms dense mats and outcompetes native wildflowers for space and nutrients

Troubleshooting Large-Flowered Tickseed

What you'll see, why it happens, and what to do about it.

Powdery white coating on leaves, usually appearing mid-summer when nights cool down

Likely Causes

Powdery mildew (Erysiphe cichoracearum) — worse in humid conditions with poor airflow
Plants spaced too tightly at under 12 inches, trapping moisture between foliage

What to Do

1.Cut affected stems back hard — Coreopsis grandiflora rebounds quickly from aggressive pruning
2.Thin the clump if it's crowded; open spacing to at least 12-18 inches between plants
3.Apply a diluted neem oil spray (2 tsp per gallon) every 7 days until symptoms stop spreading

Stems rotting at the base, plant wilting despite adequate soil moisture

Likely Causes

Crown rot (Sclerotinia sclerotiorum or Rhizoctonia solani) — almost always triggered by consistently wet, poorly drained soil
Mulch piled directly against the crown, holding moisture against the stem

What to Do

1.Dig the plant, cut away all soft rotted tissue, and replant only if a firm, healthy crown remains
2.Work coarse sand or fine gravel into the bed before replanting — Coreopsis wants lean, fast-draining soil, not amended loam
3.Pull mulch back 2-3 inches from the base of the plant going forward

Leaves stippled with tiny pale dots, bronze or silvery sheen across the foliage

Likely Causes

Twospotted spider mite (Tetranychus urticae) — flares up during hot, dry spells above 85°F
Overhead irrigation that wets foliage without raising humidity enough to deter mites

What to Do

1.Blast the undersides of leaves with a firm stream of water — does more than most people expect
2.Apply insecticidal soap (1 tbsp per quart of water) directly to leaf undersides every 5-7 days for 2-3 applications
3.Back off nitrogen fertilizer; soft new growth is exactly what mites prefer

Plant flowers heavily in year one, then thins out and blooms poorly by year three

Likely Causes

Natural clump exhaustion — Coreopsis grandiflora is a short-lived perennial, often behaving closer to a biennial in heavy clay soils
Center of the clump dying out while the outer edges stay green, a reliable sign the plant needs division

What to Do

1.Divide every 2-3 years in early spring before growth exceeds 3 inches — dig the whole root mass, split into fist-sized sections, and replant the vigorous outer pieces
2.Deadhead spent flowers consistently through the season to redirect energy away from seed set
3.If the original site has heavy clay, amend with compost and grit before replanting divisions

Frequently Asked Questions

How long do Large-Flowered Tickseed flowers last in a vase?▼

Cut flowers typically last 7-10 days in fresh water. Change the water every 2-3 days and trim stems at an angle for optimal hydration. Keep the vase in a cool location away from direct sunlight and ripening fruit, which produce ethylene gas that shortens flower life. Remove any lower leaves that would sit below the water line to prevent bacterial growth.

Is Large-Flowered Tickseed good for beginners?▼

Yes, absolutely. Large-Flowered Tickseed is an easy-to-grow perennial that thrives with minimal care. It's drought-tolerant once established, requires little fertilizer, and needs no deadheading for continuous blooms. It naturally resists pests and diseases, making it ideal for novice gardeners. Its hardy nature (USDA zones 4-9) means reliable performance across most regions.

Can you grow Large-Flowered Tickseed in containers?▼

Yes, it grows well in containers. Use a pot at least 12 inches deep with well-draining potting soil. Place the container in a location receiving 4-6 hours of partial shade daily. Water when the top inch of soil is dry. Container plants may need more frequent watering than ground plants. Divide every 2-3 years to maintain vigor and flowering.

When should I plant Large-Flowered Tickseed seeds?▼

Sow seeds directly outdoors after the last spring frost, or start seeds indoors 6-8 weeks before your last frost date. Seeds need light to germinate, so scatter them on the soil surface without covering. They germinate in 7-14 days at 70°F. You can also divide established plants in spring or fall for faster flowering results.

How often does Large-Flowered Tickseed bloom?▼

Large-Flowered Tickseed blooms prolifically from late spring through summer (May-September), producing continuous golden-yellow flowers for 4-5 months. Deadheading spent flowers encourages more blooms, though this isn't strictly necessary. In ideal conditions with consistent moisture, blooming can extend into early fall. It's a reliable performer for season-long color.

Does Large-Flowered Tickseed attract pollinators?▼

Yes, it's highly attractive to butterflies, bees, and other beneficial insects. The open-faced flowers provide easy access to nectar and pollen. Planting Large-Flowered Tickseed in groups creates a focal point for pollinators. It's an excellent choice for native plant gardens and pollinator-support landscapes, supporting local bee and butterfly populations.