The carefree flower of summer - growing the coreopsis

Flower & Garden Magazine, June-July, 1993 by Molly Dean

With the Onset of June come the summer flowers, often cheerier and brighter than their spring counterparts. And what could be more summery than the bright gold of the coreopsis, one of the easiest of all flowers to grow and one of the most beautiful?

A member of the sunflower family, this plant is found wild in fields and meadows from Michigan all the way south to Florida and New Mexico. The name coreopsis is derived from Greek "opsis" meaning "resemble" and "koris," meaning "bedbug." Its seeds, possessing two horns, might be said to remind one of a bedbug. It is not surprising, then, that a common name for the coreopsis is tickseed, due to some people's opinion that the seeds look like ticks.

Whichever bug the seeds actually resemble, the flowers that produce them are very lovely, usually with dark centers composed of disk florets surrounded by bright yellow petallike ray florets. These flowers are produced throughout the summer on long stems above mounded foliage. Many of their cultivar names are associated with lights of the sky - from the dramatic golden blossoms of |Sunray' and |Early Sunrise' to the shimmery, delicate flowers of |Moonbeam.'

One common form, Coreopsis lanceolata, produces abundant 3-inch-wide yellow daisylike blossoms upon stalks up to 2 feet high from June to frost. Although a true perennial and long-lived, this plant, unlike its cousins, seldom benefits from division. It is often confused with Coreopsis grandiflora, a species best known for its popular named varieties.

C. grandiflora has a shorter blooming season - June to July - but makes up for it with the glorious abundance of its blossoms. My grouping of five or six |Sunray' plants produces a riot of sheer golden double and semidouble flowers, unfailingly drawing our eyes and attracting hordes of butterflies. Other popular C. grandiflora varieties include |Goldfink,' a dwarf variety that stays under 12 inches tall; |Early Sunrise,' noted for its compact habit and semidouble blossoms; and |Mayfield Giant,' with extra large blossoms in a bright yellow color accented with red-brown markings.

Possibly the prettiest of coreopsis species is C. verticillata. The name means "thread-leaved" and the plant is so called because its leaves appear to be divided into silky threads. Its blossoms are a good deal smaller and more delicate - only 1 to 2 inches across - than those of the other kinds of coreopsis, and the whole effect of the plant, even when it becomes very bushy, is soft and airy. The species can grow to a full 3 feet in height. My favorite cultivar, |Moonbeam,' limits its growth to 18 or 24 inches and is covered for several months with dainty, pale yellow flowers. |Zagreb' grows even lower, to about 12 inches, and displays bright yellow blooms over ferny foliage.

Coreopsis auriculata grows from 1 to 3 feet tall and has toothed, orange-yellow flowers. A popular variety, |Nana,' a true subject for a rock garden, attains a height of only 6 inches but spreads into a broad clump. With deadheading, the cheerful golden flowers will continue into fall.

A distinctly different color is provided by Coreopsis rosea, the pink coreopsis. It is similar in form, foliage and blooming period to |Moonbeam,' but it prefers a somewhat moister soil than most coreopsis. The blossoms are a delicate rose-pink. C. rosea |Alba' blooms in an even paler shade of pink; the flowers fade to creamy white in sun.

Coreopsis is not a demanding plant. Even neglected specimens in fields or wild gardens will thrive happily for years and continue to multiply. It will grow in most types of well-drained soil. As might be expected, coreopsis is a real sun lover. It can be left alone except for an occasional feeding, deadheading, and a little watering during unusually dry periods. Of all varieties, C. verticillata most easily withstands heat and drought.

Coreopsis is sometimes affected by disease, especially if it isn't satisfied with current climatic conditions. Leaf spot, rust and mildew are the most common offenders. As a remedy, try moving the plant to a sunnier location or adding compost to the soil around it. Though it isn't usual, aphids and leaf-chewing bugs can be a problem.

You will find that coreopsis is very easily grown from seed; some even self-sow to form colonies. Sow seeds indoors six to eight weeks before the last spring frost in order to have flowers the first year. Seeds should not be covered and should be kept at 60 to 70 degrees to ensure good germination. You can also sow the seeds outside up to about two months before the first fall frost. The first flowers will appear the following season.

Coreopsis makes a beautiful and enduring cut flower - and cutting the blossoms will encourage the plant to bloom even more. Remove faded blossoms unless you want an abundance of baby plants invading your garden.

Butterflies adore coreopsis (next to purple flowers, butterflies like intensely yellow blooms best), so gardeners wanting to attract butterflies would do well to include coreopsis in their plans. In fact, for almost any sort of garden, a hardier, more beautiful flower would be difficult to find.