Mother Nature's Montrose Garden: July 2021

Plains (Dyers) Coreopsis (Coreopsis tinctoria): Great native wildflower for home gardens

Seems like one long heatwave this summer in the Western U.S. Here on the Western Slope of Colorado, I think we’re going for the gold! Cheerful garden flowers can soothe when the heat threatens to get you down. And when the plants are also easy-to-grow? That sounds like Plains Coreopsis (Coreopsis tinctoria). The scientific name is pronounced cor-ee-OP-sis tinc-TOR-ee-uh.

Plains coreopsis has been given several scientific names over the years: Calliopsis bicolor; Coreopsis atkinsoniana; Coreopsis cardaminefolia; Coreopsis similis; Coreopsis stenophylla; and several named varieties of Coreopsis tinctoria. You can still see this species being sold as Calliopsis in the nursery trade.

Among the many common names given this species are Dyer’s coreopsis, Golden tickseed, Garden calliopsis, Elegant coreopsis, Good neighbors calliopsis, Cress-leaved coreopsis and Nuttall’s weed. The name Coreopsis comes from the Greek words koris (bug) and opsis (like); the shape of the seed resembles a bug or tick. [1] The specific name, tinctoria, refers to the plants properties as a dye plant (more below).

Plains coreopsis is native to much of the western and southern U.S. and is particularly common in the Great Plains states. In Colorado, Coreopsis tinctoria is native to the northeastern counties. But the species is widely planted throughout the U.S. and Europe, and has naturalized in areas outside its native range. In the wild, Plains coreopsis is found in moist – often disturbed – places such as prairies, plains, meadows, pastures and roadsides.

Plains (Dyers) Coreopsis (Coreopsis tinctoria): growth habit

Plains (Dyers) Coreopsis (Coreopsis tinctoria): foliage

Coreopsis tinctoria is an herbaceous annual (sometimes a short-lived perennial). It grows 1-4 ft (0.3-1.3 m.) tall and 1-2 ft wide. In our experience, the plant grows taller and fuller with more water. The plants are upright with stiff stems and lacy foliage. The leaves are simple- or double-pinnate and medium green in color (above).

Plains (Dyers) Coreopsis (Coreopsis tinctoria): flowering plant

Plants flower from summer to fall, depending on local conditions. Plants can flower for a month or more, particularly if faded blooms are dead-headed. The flowers are compound (typical for Sunflower family), with dark maroon disc flowers (center) and ray flowers that may be yellow with a maroon dot/splotch or almost entirely maroon (above). A single plant can have a range of flower color variants.

Plains (Dyers) Coreopsis (Coreopsis tinctoria): close-up of flower head

The flowers face the sun, moving on their slender stalks throughout the day. Grow Coreopsis where you can enjoy their spectacular colors, with the sun at your back. And don’t hesitate to harvest some flowers to enjoy indoors. They make good cut-flowers and add a nice touch of color to a mixed bouquet.

Coreopsis tinctoria re-seeds nicely in many gardens, so this is an easy plant to naturalize. Just leave at least some flowers to produce seeds. When the flowering heads are dry (about 4 weeks after flowers fade), scatter the seeds where desired. Alternatively, you can clean the seeds and save them for planting in the spring. Rub the dried flower heads between gloved hands, releasing the small seeds. Gently blow away the chaff, then store fully dry seeds in a sealed container in a cool place.

Plains (Dyers) Coreopsis (Coreopsis tinctoria): emergent seedlings

Plains (Dyers) Coreopsis (Coreopsis tinctoria): seeedlings ready to plant out

Seeds can be planted in prepared beds in spring or grown in pots indoors and then planted out. Seeds need no pre-treatment and are easy to grow. Barely cover the seeds - they need light to stimulate germination. The photos above show seedlings at two different stages. Note that the emerging leaves are simple compared to mature leaves.

Plains coreopsis is not a fussy wildflower. It will grow in most soils and does well in full or part-sun. It is said to favor a wide range of soil pH – from 5 to near 8 (Mother Nature’s Montrose Garden). Young plants need good soil moisture, but taper off the water as plants become established (and particularly after they start to go to seed in later summer or fall). In our garden it has not experienced any serious pests or diseases, although slugs or snails might be bothersome in a moister climate. Taller plants may need support if you live in a windy area.

Plains (Dyers) Coreopsis (Coreopsis tinctoria): pollinator

Plains (Dyers) Coreopsis (Coreopsis tinctoria): bee pollinator

So, why grow Coreopsis tinctoria? Well, it’s an easy-to-grow annual wildflower that can be grown in small places, including in containers. Its flowers add a cheery note to any garden – large or small. If you desire to create habitat, this is a great plant for native pollinators and birds. The flowers ‘provide nectar and pollen to a wide variety of insects, including long-tongued bees, short-tongued bees, wasps, flies, butterflies, skippers, and beetles.' [2] We’ve noticed that some bee species seem particularly drawn to the darker flowers, while others visit the bi-color flowers (above). And seed-eating birds will thank you for the seeds.

Plains (Dyers) Coreopsis (Coreopsis tinctoria): dye bath

Plains (Dyers) Coreopsis (Coreopsis tinctoria):dyed yarn

The flowers contain several chemicals used as natural dyes. Colors ranging from yellow to mahogany can be produced by altering the pH of the dyebath. The dyes are readily released from fresh or dried flower heads. Just pour hot water over the flowers and wait an hour or so. The red colored water can be used to dye wool or silk. The red dye chemicals will attach first, then the yellows, so different colors can be obtained from a single dye bath. We’ll talk more about natural dye methods in a future posting.

Coreopsis tinctoria has a medicinal tradition as well. An infusion (tea) from the plant has been used as a tonic, and for internal pains and bleeding. Zuni women desiring a female child would also drink such an infusion. [3, 4]

Plains (Dyers) Coreopsis (Coreopsis tinctoria): in
Mother Nature's Montrose Garden

Plains coreopsis provides cheerful summer color in the garden. It looks spectacular when massed or contrasted against green background foliage. It’s a good filler around growing shrubs and perennials. Some gardeners include it in a cuttings garden or herb garden. It will attract a range of pollinators if planted among your vegetables. It is also effective when combined with native grasses and other native wildflowers for a meadow or prairie planting.

Plains (Dyers) Coreopsis (Coreopsis tinctoria): flowers contrast
well with green background foliage

Seeds are readily available from many on-line seed sources. If you desire specific characteristics, you can choose from several available cultivars. But the straight species is a delight, so there’s something for everyone. Plan to order some seeds this summer for fall planting. You’ll be the envy of your friends and neighbors next summer (and you’ll be able to share some seeds)!