Coreopsis verticillata L.

Coreopsis verticillata is a North American species of tickseed in the sunflower family. It is found primarily in the east-central United States, from Maryland south to Georgia, with isolated populations as far west as Oklahoma and as far north as Québec and Ontario.^[1] The common names are whorled tickseed,^[2][3] whorled coreopsis, thread-leaved tickseed, thread leaf coreopsis, and pot-of-gold.

Description

Coreopsis verticillata is an herbaceous perennial that grows 2–3 ft (1–1 m) tall and about 2 ft (1 m) wide, although as it spreads laterally by rhizomes,^[4] this width can be exceeded. The stems are wiry.^[5] The flower heads are up to 2 in (51 mm) across, and both the disc florets and ray florets are bright yellow. The flowers are produced abundantly in clusters from midsummer to fall.^[6]

Habitat

Coreopsis verticillata can commonly be found in dry, thin woods and open pinelands, preferring sites with full sun exposure. It can tolerate drought, poor soil, extreme heat, and neglect.^[5]

Horticultural cultivation

Coreopsis verticillata and its horticultural cultivars are not difficult to grow and hence make good starter plants for beginning gardeners in the U.S.^[7] They have a long flowering season and are relatively free from pests and diseases.^[7] They attract butterflies and are deer resistant.^[7] They can be grown in hanging baskets and containers (where irrigation will be necessary), or as border plants.^[8] Carolyn Singer, in "Deer in My Garden", reports that C. verticillata is a good companion plant with other summer-blooming perennials requiring similar conditions.^[9] The following notable cultivars have gained the Royal Horticultural Society's Award of Garden Merit:

• 'Grandiflora' - taller than other cultivars, with slightly larger flowers^[10]
• 'Moonbeam' - pale, sulphur-yellow flowers, slightly shorter growth, chosen as the 1992 Perennial Plant of the Year by the Perennial Plant Association.^[5] When this cultivar was first introduced to the market, demand outstripped supply in some localities, such was its popularity.^[11][12]
• 'Zagreb' - shorter than the species, bright yellow flowers^[13][14]

References