Bigflower Coreopsis, Largeflowered Tickseed, Tickseed Coreopsis 'Mayfield Giant'

Coreopsis grandiflora

Family: Asteraceae (ass-ter-AY-see-ee) (Info)
Genus: Coreopsis (kor-ee-OP-sis) (Info)
Species: grandiflora (gran-dih-FLOR-uh) (Info)
Cultivar: Mayfield Giant



Foliage Color:

Unknown - Tell us

Bloom Characteristics:

Unknown - Tell us

Water Requirements:

Requires consistently moist soil; do not let dry out between waterings

Where to Grow:

Unknown - Tell us


12-18 in. (30-45 cm)


24-36 in. (60-90 cm)


USDA Zone 4a: to -34.4 °C (-30 °F)

USDA Zone 4b: to -31.6 °C (-25 °F)

USDA Zone 5a: to -28.8 °C (-20 °F)

USDA Zone 5b: to -26.1 °C (-15 °F)

USDA Zone 6a: to -23.3 °C (-10 °F)

USDA Zone 6b: to -20.5 °C (-5 °F)

USDA Zone 7a: to -17.7 °C (0 °F)

USDA Zone 7b: to -14.9 °C (5 °F)

USDA Zone 8a: to -12.2 °C (10 °F)

USDA Zone 8b: to -9.4 °C (15 °F)

USDA Zone 9a: to -6.6 °C (20 °F)

USDA Zone 9b: to -3.8 °C (25 °F)

Sun Exposure:

Full Sun



Bloom Color:

Bright Yellow

Bloom Time:

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall


Unknown - Tell us

Other details:

Unknown - Tell us

Soil pH requirements:

Unknown - Tell us

Patent Information:

Unknown - Tell us

Propagation Methods:

From seed; direct sow outdoors in fall

From seed; direct sow after last frost

Seed Collecting:

Collect seedhead/pod when flowers fade; allow to dry

Allow seedheads to dry on plants; remove and collect seeds


This plant has been said to grow in the following regions:

Urbandale, Iowa

Manns Harbor, North Carolina

Gardeners' Notes:


On Jan 29, 2010, BajaBlue from Rancho Santa Rita, TX (Zone 8a) wrote:

36-48” x 18” wide (Seed propagated)

‘Mayfield Giant’ is the tallest and most robust of all the Coreopsis grandiflora cultivars. Its dazzling display of large 3” golden yellow daisies begins in late spring and continues through summer with regular deadheading.

This English selection has unusually glossy foliage that is highly resistant to the powdery mildew that can trouble some ‘grandiflora’ types. ‘Mayfield Giant’ has vigorous, deep-reaching
roots and grows in any well-drained soil.

Combine it with other big summer bloomers like Perovskia (Russian Sage) in a hot sunny location. Zones 4-10.

Special Notes: High Country Gardens Plant of the Year!


On Jun 12, 2006, DrDoolotz from Oxford, NS (Zone 5b) wrote:

This is a great plant - it is taller than 18 inches for me - more like 24 to 36. The flowers get a bit floppy and I have recently tied them loosely to a stake to keep it under control. The flowers are just constant and they really add some lovely colour to the area beside my birdbath. I transplanted mine last fall after flowering was finished and they came back in spring with amazing energy. I think this is a very low maintenance and easy plant that gives a great show!