Coreopsises, also known as tickseed, are reliable perennial flowers for a sunny border. Hailing from eastern and central North America, they are emblematic of the beauty and simplicity of the United States's native flora.
Coreopsises are sun-loving, long-blooming wildflowers that form clumps two to four feet tall and wide. The flowers are usually yellow though other warm-toned colors are available. It is not unusual for the blossoms to cover the plants for six months of the year or more. The flowers are one to two inches in diameter and daisy-like - not very showy individually, but quite impressive when several plants are massed together.
The foliage is equally inconspicuous - most varieties have simple lance-shaped leaves - but the beauty of these plants is their overall effect in a flower border, their ability attract butterflies and their general ease of growing.
Coreopsis is easy to grow from seed and is commonly found in wildflower mixes. Sow the seed directly where you want the plants to grow outdoors in fall or early spring in a sunny position, covering with just a thin layer of soil. Keep the area moist and they should germinate within a week or two.
- Care - They appreciate good drainage, but otherwise they are very adaptable to soil type - low fertility is not a problem. Coreopsis is modestly drought tolerant, but should be watered whenever there has been several weeks without rain.
- Trimming - They will start blooming as soon as the nights stay warm in spring. The key to keep them blooming is to trim off the flower stalks as they fade. This is quickly accomplished with a pair of garden shears. Depending on the length of the growing season, there may be three or four rounds of flowers in one year.
- Self seeding - Coreopsis often seeds itself in the garden. Leave the last round of spent flowers to go to seed if you want the plants to spread themselves.
Flowering will cease when the nights cool off in fall and the foliage will turn brown with the first hard freeze of winter. Cut the foliage to the ground, cover the root zone with a layer of mulch and wait for the magic to begin again the following year.
Division is not necessary with coreopsis and no further maintenance is generally needed. However, the plants are naturally short-lived and individual specimens should not be expected to persist more than three or four years.
Pests and Disease
Coreopsis are generally tough and hardy plants, rarely bothered by pests and disease. It's important not to over-water them or plant them in very rich soil as these conditions will predispose the plants to health problems.
Fungal leaf spots may occur on the leaves in wet years and mites and aphids may occasionally show themselves. Rather than investing a lot of time in treating these minor problems, the simplest approach is to cut the plants back about half way to the ground - the issue will often disappear by the time the plants regrow.
Coreopsis is commonly available in nurseries throughout the country, including a number of improved landscaping cultivars.
- 'Moonbeam' has soft yellow flowers and unusual foliage that appears as thin, almost threadlike leaves. It's hardy in USDA zones 3-9.
- 'Brown Eyes' has yellow flowers with a reddish brown center. It's suitable for USDA zones 2-9.
- 'Baby Gold' is a dwarf selection with yellow flowers growing about 12 inches tall. Plant it in USDA zones 5-9.
- 'Rosea' has rose-pink flowers and thin, threadlike leaves. It's hardy in USDA zones 4-8.
A Sunny Disposition
Coreopsis flowers are a bright sunburst of color in the garden. Full of butterflies and easy to grow, they are a perfect fit in the perennial border.