Perennial flower gardeners really appreciate plants with an extended season of bloom. The perennial flower that immediately comes to my mind when thinking of long bloom is coreopsis. Coreopsis, also called tickseed, possess daisy-like flowers in various shades of yellow to dark gold to almost orange. A newcomer to the numerous coreopsis offerings is Coreopsis rosea, the only pink form. Flowering of many varieties begins in late spring and continues through most of the summer.
There are several species of Coreopsis to select from offering a range of plant heights from less than 1 foot to almost 4 feet. Although some have a sprawling habit, many are well-behaved, compact plants that combine perfectly with other flowers. Most coreopsis are hardy to USDA Hardiness Zone 4, a real plus for northern gardeners. Other advantages include drought tolerance, poor soil adaptability, and durability. They perform best in full sun or light shade.
Some of my favorites include C. grandiflora `Sunray' and `Early Sunrise'. Both have double flowers and grow to about 2 feet in height. Thread leaf coreopsis (C. verticillata) has foliage divided into thread-like segments. `Golden Showers' grows up to 2 feet tall with bright yellow flowers. `Moonbeam' is probably the most popular cultivar and with good reason. The 2 foot plant bears numerous soft yellow flowers from late June through October. `Zagreb' is a compact, upright plant with flowers in a darker shade of yellow than `Moonbeam'. C. lanceolata and its cultivars have single flowers which are up to 2 1/2 inches across. `Brown Eyes' has a maroon ring near the center of the flower. `Baby Sun' and `Baby Gold' are smaller varieties, each growing only 10 to 16 inches tall. These make excellent selections for use as edging or rock garden plants.
Coreopsis are pest resistant. Leaf spots may be a problem especially in wet years, but they usually don't affect the first bloom. Cut plants back severely after flowering and the new growth will be strong and healthy. The only disadvantage of coreopsis is the necessity of deadheading. Trim spent flowers off regularly to promote continuous production of new flowers. If not deadheaded, only naked flower stalks will remain above the foliage. Propagation is accomplished through seed, cuttings, or division. Named cultivars should be propagated vegetatively rather than through seed to ensure true identity.
Coreopsis can also be used as fresh cut flowers, especially those with long flower stems. At the end of the flowering season, allow seeds to remain for the birds to enjoy. Not many plants offer season-long beauty, both indoors and out, and also provide food for our feathered friends. Coreopsis is a highly valued perennial for many garden settings. Plant one of my favorites or select one of your own.
This article originally appeared in the June 23, 1993 issue, p. 101.