Zone: 4 to 9
Soil: Sand to loam
Light: Full sun to part sun
Bloom colour: Yellow and pink
Bloom period: The whole summer
Height: Usually 15 inches but up to 10 ft.
Moisture: Dry to medium
Attracts: A variety of small bees, bumblebees and syrphid flies. It also attracts butterflies.
Notes: If you have dry sandy soil and lots of sunshine, then Coreopsis is an excellent plant. Threadleaf Coreopsis is a low maintenance plant that flowers all summer if deadheaded. It grows to about 15 inches high and forms a spreading clump that will eventually fill in the space that has been allocated to it.
If you want, a taller coreopsis with more prominent flowers then plant Coreopsis grandiflora or Coreopsis lanceolata. Coreopsis lanceolata, a native of Ontario, is one of those plants that has a happy-go-lucky look to it. It flowers for a long time and is appealing when mixed with other plants.
Tall coreopsis (Coreopsis tripteris) grows over 8 ft. high. With its thick spray of flowers and its bamboo-like leaves, it can provide a fabulous backdrop to show off other perennials in August and September. It is far more impressive when planted in groups and it is the best species of Coreopsis to attract wildlife. It draws both butterflies and a wide variety of bees. The hollow stems can also be used to make bee houses. In part sun, it will definitely need support, which may be aided byplacing other quite tall plants in front of it. Choose a companion plant that flowers at the same time for best effect. In the photograph shown here, it has been planted behind Joe-Pye Weed. Great Blue Lobelia would be another good choice.
Coreopsis lanceolata and Coreopsis tripteris are both native to Ontario. The other species mentioned are native to other parts of N. America. The former is a plant suitable for the middle of the border in regions with dry sandy soil while the latter prefers mesic soil conditions and is suitable for the back of the border.
The pink varieties of this genus come from Coreopsis rosea which requires more water than other species. In Canada, this plant is only native to Nova Scotia.
There is an annual species called Coreopsis tinctoria or Plains Coreopsis, which has small red flowers with a yellow border. It grows to about two or three feet and tends to attract syrphid flies. To give it more support, it can be planted amongst other plants. Monarda punctata is a good choice for a companion plant since they do well in slightly dry sandy soils. Coreopsis tinctoria will reseed itself each year.
Some species of Melissodes have a close relationship with Coreopsis.