Coreopsis ‘Gold Standard’ (photo by MT Cuba Center)

Coreopsis ‘Last Dance’ (Photo by MT Cuba Center)

Coreopsis (Coreopsis spp.) are flowering perennials (and annuals) native to the eastern U.S. In 2016, MT Cuba Center* in Greenville, Delaware reported on the overall garden performance of 13 species and related cultivars and hybrids in the Mid-Atlantic region. Over a period of 3 years, the MT Cuba staff evaluated habit, floral display, disease resistance, and longevity. Several popular cultivars performed poorly because of disease susceptibility and winter survivability.

Four underutilized native species and cultivars earned outstanding performance ratings. All four also displayed excellent resistance to powdery mildew, downy mildew, and leaf spot diseases.

‘Summer Sunshine’ coreopsis (C. palustris ‘Summer Sunshine’) is the highest-rated coreopsis in the 3-year trial. Vigorous mounds of foliage grow to 30 inches tall and remain lush, sturdy, and dense all season long. In late September plants are covered with golden yellow flowers with dark central cones. The amazing display lasts for six weeks, and provided an important late-season food source for pollinators. ‘Summer Sunshine’ is a rhizomatous selection that slowly increases in size by 2.5 feet over three years.

Coreopsis ‘Flower Tower’ (photo by Mt Cuba Center

‘Flower Tower’ coreopsis (C. tripteris ‘Flower Tower’) appropriately named, towers over the competition at an astonishing 8 feet tall. Stems are thick and sturdy and capable of staying vertical in even the strongest winds. It is the tallest coreopsis in the trial, and also has the largest flowers, measuring 2½ inches across. ‘Flower Tower’ is perfect for large-scale landscapes, perhaps not in average sized gardens. This rhizomatous selection spreads very slowly, about 2 feet over three years.

‘Gold Standard’ coreopsis (C. tripteris ‘Gold Standard’) is another superior selection that typically grow to 7 feet tall, with a floppy habit and uninspiring floral display. ‘Gold Standard’ is a slightly shorter (5½ feet tall) and has incredibly sturdy stems. By late July, a multitude of sunshine yellow flowers appear above the robust foliage in mid-August and the floral display lasts over two months. ‘Gold Standard’ has a rhizomatous habit and spreads slowly (about 2 feet over 3 years).

‘Last Dance’ coreopsis (C. integrifolia ‘Last Dance’) is a fall-blooming tickseed whose uniformly compact habit is a vast improvement over other versions of C. integrifolia. ‘Last Dance’ is slow to emerge in the spring. It often does not reach 1 feet tall until June, and eventually tops out at only 2 feet tall. The 2 inch, extra-large, golden flowers have strongly pleated petals which make them look thick and substantial. ‘Last Dance’ is the last tickseed to flower, blooming throughout October. ‘Last Dance’ spreads via rhizomes at a rate of about 12 inches per year.

 *Blog readers are encouraged to read the entire Coreopsis Report on the Mt Cuba website.