All About Coreopsis
Profuse blooms, often in shades of yellow, through a long period in mid-summer make coreopsis a great native plant choice for perennial gardens and containers.
This perennial has even more going for it—low maintenance with few insect pests or disease problems, if any.
Coreopsis attracts butterflies, beneficial insects, and birds
In addition to butterflies and insects, coreopsis is a good choice for birds, IF you let plants form for the seeds.
The only problems are, that by doing so, you’ll get fewer flowers and they may self-sow throughout your garden where you don’t want them. One compromise is to keep them cut back during the season, for more flowers, but let them go to seed in the fall for the birds. You may, then, have to easily weed out some seedlings next spring if they self-sow.
Coreopsis (said as “core-ee-OP-siss”)-- the name that it is most often known by-- also has the common name of “tickseed” from the resemblance of seeds to ticks. This is a good example of a common name that really doesn’t do justice to a wonderful flower that is in the daisy or aster family (Asteraceae).
The name “coreopsis” also refers to the seeds, coming from the Greek words “koris” meaning bug, and “opsis” meaning “like a bug.”
Coreopsis were popular some decades ago when mainly the species were sold and there were only a few selections. Those growing them were the original native plant enthusiasts.
In recent years coreopsis has become much more popular, grown, and sold thanks, in part, to the breeding of many new forms. There are at least 80 different species of coreopsis and many selections and hybrids of them. About half the species are native to North America, the other half to Central or South America.
Life Cycle
Some coreopsis are perennial—living more than one year, others are annual—living for only one year.
So it’s important when shopping for, and choosing, which coreopsis you’ll plant to find out first if the desired plant is annual or perennial in your area. Some may be perennial in warmer climates, but not live over winter in colder climates.
Use annual coreopsis in front of taller summer perennials such as garden phlox, bee balm, or coneflowers. Annual coreopsis also looks great in containers on patios or balconies.
Growing Coreopsis
Make sure to check the hardiness zone ratings on the plant description or label.
While hardiness zone is a good place to start with the perennial species, there is more to winter survival with coreopsis than just temperature.
Soil plays a big part in winter hardiness. Coreopsis survive much better in sandy soils and those that stay dry during winter, rather than staying too wet.
The Mt. Cuba, Delaware trial of 94 different coreopsis found that those that spread by underground stems (rhizomes) were much more likely to overwinter successfully than those that formed clumps.
The annual species and its selections may perform better through the summer into fall with regular watering and fertilizer. Cutting off spent flowers (deadheading) individually takes some time, but results in a more continual bloom than shearing all off. The latter is quicker and easier but may leave the plants with no blooms for 3 weeks.
Most Common Types of Coreopsis
Although there are many perennial species of coreopsis and, in fact, most are perennial in many areas, there are a handful that are most common. The perennial species are generally deer resistant—an important trait for gardeners in many parts of the country.
Coreopsis tinctoria or Golden tickseed or Plains coreopsis
The most common annual species that you’ll find, along with some selections of it, is the golden tickseed or plains coreopsis (tinctoria), native as its name indicates to the plains of the Central U.S. but also to much of the East and the South.It has spread throughout many western and southern states where it can be found in disturbed areas, such as ditches along roadsides.
It has small, but many, yellow flowers with red centers in summer on plants one foot or so high. Tips of petals have notches in them
Coreopsis auriculata or Mouse-ear coreopsis
The mouse-ear coreopsis(auriculata) gets its great name from the two sections of the leaves that stick out like mouse ears. The yellow spring flowers appear above the dark, evergreen foliage. As with the annual coreopsis, this and most the perennials reach 1 to 2 feet tall.
Although native to southern states, it is hardy in USDA zones 4 through 9 which means they can tolerate minus 30 to 30 degrees F average annual winter minimum temperature. Check your zone with the USDA Hardiness Zone Interactive Map
Coreopsis 'nana' or Dwarf mouse-ear coreopsis.
Even lower is a dwarf mouse-ear coreopsis (‘Nana’) which, like the species, spreads but not aggressively. It only reaches 6 to 8 inches high. Plant several of these a foot or so apart to fill in and make a nice colorful mass of flowers in spring.
Coreopsis grandiflora or Large-flowered coreopsis.
Another popular perennial coreopsis is the large-flowered coreopsis (that’s what the species name grandiflora means), with quite a few popular selections. It begins flowering in early summer and, with deadheading, should produce more orange to yellow flowers throughout the summer.
It, too, is native to southern states, can reach 1 to 2 feet tall, and is hardy in zones 4 through 9. The only downside with this species is that it is short-lived, needing replacing every couple of years in the South and every 3 to 4 years in the North.
Coreopsis lanceolata or Lanceleaf coreopsis
The perennial lanceleaf coreopsis (lanceolata) is another southern native, but also is found through the Midwest and is naturalized throughout northeastern states.
It is, in many respects, similar to its large-flowered relative, and may hybridize with it. This one, though, may be longer lived and has most of its leaves at the base of plants.
Coreopsis rosea
The pink coreopsis (rosea) species is native from Nova Scotia to Maryland, so performs best in zones 4 to 7. Some of its selections or hybrids may not be quite so winter hardy. What you find for sale (usually the dwarf form of the species) is under one foot high, the rose-pink summer flowers having yellow centers. It has fine, thread-like leaves.
Coreopsis verticillata or threadleaf coreopsis
Perhaps the most popular perennial tickseed is the threadleaf coreopsis (verticillata) with, as its name indicates, thread-like leaves too. It is one of the tallest coreopsis, reaching 18 to 36 inches high, and needing 2 to 3 feet to spread. It provides yellow summer flowers.
Planting Zones
The threadleaf species is native to the mid-southern states, so it tends to prefer warmer zones (5 through 9) such as central New England and the Midwest and south. A few of its selections can be grown in even colder areas, but most threadleaf selections or hybrids may be marginally hardy in zone 5 (-10 to -20 degrees F average winter minimum).
Then there are a host of hybrids of these and other species, some whose parents are unknown, providing a range of colors and bicolors from red to pink, yellow to gold and even white.
The main point to remember about all these coreopsis hybrids is that some aren’t very cold hardy for those gardening in the north. For those gardening in the south and on the west coast, these are worthy to consider. Many hybrids are good in containers, being relatively low and compact.
While it is hard to know all about coreopsis from just this article, you should now have all the basics you need to make some great choices from the many available, with selections for most any garden in the country, and their key needs for proper placement so they’ll reward you with masses of color.
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