Coreopsis Reconsidered
By Allan M. Armitage

The name Coreopsis translates to “like a bug” - that should tell you something right there. If that is not enough, its common name, based on the size and color of its seeds, is tickseed. How many bugs (or ticks) do you cherish? Most of us spend our lives trying to exterminate bugs. And as for ticks, well, my dog, Hannah, can give you her opinion of those itchy things.

These plants, however unpleasant the name, have been an important part of the American perennial plant palette for some time. For starters, there are lots from which to choose - between 80 and 120 species, depending on who’s counting - all native to North America. And certainly for a rookie gardener or a beginning landscaper, coreopsis is often a staple, because some of them - especially the familiar common tickseed (C. grandiflora), which is not one of my favorites, as you’ll see later on—are among the easiest plants to produce and therefore are always available to unsuspecting gardeners in the spring.

Most of the species are described as perennials, but in reality many of them perform in the garden more like annuals or biennials. In talking about coreopsis with a number of gardeners, I find that sentiments differ, but the comment of Judy Laushman, who is director of the Association of Specialty Cut Flower Growers and a gardener in northern Ohio, struck a chord. “When I thought about it, I realized coreopsis is one of those plants that I buy one spring, tend lovingly throughout the season, then a couple years later think, ‘Hey, didn’t I…wasn’t there…? I could’ve sworn I planted some coreopsis there’.”

In my travels around the country I have closely scrutinized these plants growing in many different regions; I have also grown many of the newer cultivars in the University of Georgia’s trial gardens in Athens. So before I start to sound like a coreopsis scrooge, let me make it clear that I applaud the work of plant breeders who are providing some outstanding hybrids. I also want to tip my hat to some of the native plant enthusiasts, especially those in the Midwest, who have been extolling the virtues of some of our lesser-known native Coreopsis species…
Getting Started with Tickseeds

Native from Georgia south to Florida and west to Kansas and New Mexico, common tickseed (C. grandiflora, Zones 4–9, 12–1), is a great beginner’s plant. It is so easy to grow in the nursery that most plants are in full flower in their containers as we push our carts through the aisles. Plants grow 12 to 15 inches tall and may bear single, double, or semi-double yellow flowers most of the season. The yellow flowers glow above the dull green leaves in the spring and continue to bloom after planting. I recommend grouping at least a half-dozen plants in the front of the garden or two to three in a container so the flowers and foliage can be appreciated. But I know you’re thinking, if this plant is so good, why am I one of its biggest critics?

The answer is that this is a great annual, or a biennial at best, and if sold as such I would be its biggest supporter. It tolerates cold temperatures, but suffers badly in the heat of the summer, often contracting diseases such as leaf spot and botrytis. It does not tolerate wet soils, so excellent drainage is essential. One of its greatest assets is also one of the gardener’s greatest challenges—Flowers are produced constantly but only if the spent flowers are deadheaded. If not removed, they become blackened and diseased and, by midsummer, the plant stops flowering, resulting in a wet dog look that over time becomes a dead dog look…

Improved cultivars have been developed, and although I don’t feel many are a great deal better than the species, here are a few that are worth a try.

‘Early Sunrise’ was an All-America Selections winner in 1989. Plants are easily raised from seed and bear bright yellow, semi-double, two-inch-wide flowers. It was a breakthrough plant for producers that allowed coreopsis to be in flower for spring sales. Although not persistent, it’s excellent for a couple of years…

‘Sunfire’ has fringed yellow ray flowers and wine-red markings in the center.
‘Sunray’ is an old-fashioned selection that has stood the test of time. Plants bear two-inch-diameter double flowers on two-foot plants for eight to 12 weeks.
‘Tequila Sunrise’, sometimes listed as a hybrid, is either the ugliest or the prettiest plant you have ever seen. Its variegated foliage is green and white with a hint of pink, topped by golden single flowers. I have always enjoyed the plant, but I seem to be in a minority. It does not have great vigor and will likely not persist for more than two years.

Lanceleaf coreopsis (C. lanceolata, Zones 3–8, 9–1) has a similar native range to common tickseed and behaves in much the same way in the garden. It grows one to two feet tall and bears golden yellow flowers on slender stems from spring to early summer…

My experience with mouse-ear coreopsis (C. auriculata, Zones 4–9, 9–1) has been much more positive, but this native of the American Southeast is an early spring-flowering plant only. Stay away from this plant if the label does not say ‘Nana’ or one of the other cultivars listed below, because the species itself is quite tall - to two feet - and not as useful for the garden.

‘Nana’ grows to about eight inches and produces dozens of bright yellow flowers over foliage that remains in good condition all season if moisture is provided. If plants dry out, however, the foliage self-destructs. Don’t expect flowers after late June in the North, late May in the South….

In addition to ‘Nana’, a couple of newer selections I quite enjoy are ‘Jethro Tull’ and ‘Zamphir’…. ‘Zamphir’ is not as good a performer as ‘Nana’, but has proven to be a winner. Plants are also dwarf, usually reaching 10 to 15 inches. The flowers are a golden yellow, but what is most unusual is that the ray flowers are “open” at the ends, and look like wine flutes, quite different from other cultivars. ‘Jethro Tull’, which originated from ItSaul Plants in Georgia, resembles ‘Zamphir’ but is even better. It has more consistently fluted ray flowers. We have enjoyed this 12- to 15-inch-tall selection in the trial gardens because it has a long flowering period and quite special flowers…

Evaluating the Hybrids

If anything in the horticulture industry has changed in the last 10 years, it is the modernization of native plants, including tickseeds. Some people hate the idea that our native plants have been used in commerce as parents for hybrids, but without a doubt, if it were not for selection and breeding, many of our native plants would not be nearly as popular.…

‘ ‘Heaven’s Gate’ (Zones 5–8, 9–5) is another one of the many colorful dwarf cultivars that have arisen lately. This one has thin stems topped with rose-pink flowers, each with a darker center. Plants grow about a foot tall and equally wide…

Photo credits: All photos of coreopsis by Allan Armitage.

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