Jennifer Schultz Nelson
Extension Educator, Horticulture
This time of year I am on the lookout for plants that still look good in the garden. Most plants look pretty tired and haggard by late August. Adding in some plants that are starting to bloom or still blooming by late summer breathes some life into a tired landscape.
If you're looking for a real workhorse of a plant for your perennial garden, consider Coreopsis. Many cultivars of this plant flower beginning in spring and continue into the fall. Most cultivars are right around two feet tall, making them a good medium sized plant in the perennial garden.
A big factor that contributes to Coreopsis' work horse reputation is that many of the cultivated species are native to North America, so they are well adapted to our climate.
Coreopsis, also commonly called tickseed or calliopsis, is a genus from the family Asteraceae, the plant family that includes familiar members like daisies and black-eyed Susans. The family resemblance is apparent looking at Coreopsis-- each flower is daisy-like, usually less than two inches in diameter, typically with petals that have a toothed tip.
Most Coreopsis flowers are yellow. However there are more and more cultivars being introduced that broaden the color palette into reds oranges, pinks and white. A few cultivars to consider:
Foliage is another variable to consider among different species and cultivars of Coreopsis. Leaves may be deeply cut, or even fern-like and thready. One fern-leaved cultivar I have in my garden is 'Zagreb', a yellow-flowered cultivar. Its thready foliage is a nice contrast to plants with broader leaves. It flowers most of the summer into fall, and the flowers appear to float among the foliage.
Another cultivar with unique foliage is 'Tequila Sunrise'. This Coreopsis has deeply cut foliage with cream colored variegation and bright yellow flowers. Even when not in bloom this plant is beautiful. I have noticed though that occasionally solid green, or revertant sections appear in this plant.
This is not unusual for a variegated plant. The variegated foliage is genetically a mutant, and occasionally Mother Nature mutates a few cells in the growing point back to the "normal" solid green. I keep my plant variegated by removing the solid green sections as they appear.
Coreopsis typically holds its flowers on wiry stems well above the foliage. To keep Coreopsis flowering consistently, deadheading is a must. The wiry stems make deadheading fairly easy, but the typical mix of spent and new flowers makes this job tedious.
It is far easier to shear off all the flower stems to deadhead in one fell swoop rather than pick through each flower stem. Sources say to shear the plant back as blooming wanes to encourage a new wave of blooms. I have done this with success, but if I have the time I will deadhead individual stems.
This year I was putting off deadheading the Coreopsis near our patio, dreading the job. One morning I noticed that the local goldfinch population was happily feeding on the Coreopsis seed heads, the wiry stems easily supporting the small birds. So I guess my procrastination made the local goldfinches pretty happy!
I have continued to leave the Coreopsis seed heads for the goldfinches. The plants are not flowering as profusely as they would when regularly deadheaded, but they are still blooming. It is still possible to shear the plants back to push a round of fall blooming, which I may do in the next week or so.
Besides their extended flowering, Coreopsis are also very drought tolerant and considered deer resistant. These hard working plants deserve a spot in your perennial garden.