How to Grow and Care for Coreopsis (Tickseed)

If you're looking for a low-maintenance, drought-tolerant, long-blooming flower to fill a bed or line a border, coreopsis plants (Coreopsis spp.) are a perfect choice. With over 80 varieties of coreopsis, there's a variety to suit every garden design. These showy, daisy-like flowers don't have much of a scent, but the foliage has an anise-like smell. They are native to North America, growing in upright clumps and flowering throughout the summer.

The species' foliage varies, with some varieties boasting large green leaves and others sporting narrower greenery. One of the plant's common names, tickseed, is a nod to its round seeds, which resemble ticks.

Plants in the coreopsis species have a moderate growth rate and are best planted in the spring after all risk of frost has passed. This hardy plant's perennial varieties grow in USDA zones 2 through 8, dying back after frost and returning in the spring; in the coldest zones, add a few inches of mulch to protect its underground roots. Annual varieties will start blooming in early summer and repeat bloom periodically through the fall, while perennial varieties will begin blooming the second year after planting from seed.

Coreopsis Care

Overall, coreopsis plants don't require much care when grown in their preferred environment. Select a planting site with lots of sun and good soil drainage. Also, don't forget to account for the mature size of your species—when planting, leave some space around each plant for air circulation.The taller coreopsis varieties might need staking as they mature; otherwise, the stems might flop over. Moreover, deadheading your plants (removing the spent blooms) can keep the plant blooming throughout summer and into fall.

Light

Coreopsis plants will grow and bloom best in full sun, which means at least six to eight hours of direct light on most days. They can also grow in partial sun, but the plants might be lankier and not flower as profusely. In climates with very hot summers, some afternoon shade is welcome.

Soil

These plants thrive in well-draining, loamy or sandy soil with a fairly neutral soil pH. However, most coreopsis varieties are straightforward to grow and aren't particular about soil quality or soil pH as long as they aren't waterlogged. Some of the most profuse blooming comes from coreopsis plants growing on the untamed border of roadways or other "forgotten" areas. Heavy, wet clay soils should be amended with compost to help drainage.

Water

New coreopsis plants need regular water to keep the soil evenly moist (but not soggy) until they are established. After their first year, these plants have good drought tolerance, but they'll bloom most prolifically with regular watering. Water deeply whenever the soil is dry, about an inch down. Early morning watering is best—it allows the leaves a chance to dry out during the day.

Temperature and Humidity

Coreopsis plants like warm temperatures between 70 and 80 degrees Fahrenheit during the day and 50 and 60 degrees Fahrenheit at night. High humidity levels typically aren't an issue for these plants as long as they have good air circulation and proper watering and drainage. That being said, various species of coreopsis have differing levels of cold tolerance.

Fertilizer

Fertilizer isn't necessary for coreopsis plants unless you have very poor soil. Too much fertilizer can promote excessive foliage growth at the expense of the plant flowering. To boost your plants, you can mix a little compost into the soil at the beginning of spring.

Types of Coreopsis

There are dozens of species and varieties of coreopsis, which mostly differ in appearance rather than care. Some of the most popular varietals for outdoor cultivation include:

• Coreopsis grandiflora'Early Sunrise':A variety with large, semi-double, bright yellow flowers that start blooming in early summer
• Coreopsis grandiflora'Golden Showers':A variety with profuse yellow blooms on longer-than-average stems
• Coreopsis verticillata 'Moonbeam':A variety with buttery yellow flowers and a compact, dense shape
• Coreopsis rosea'Nana': A mauve-pink dwarf variety that spreads nicely but lacks drought tolerance

Pruning

Cutting back the top of a declining perennial to the ground or near ground level will promote vigorous new growth, rejuvenating the plant. To encourage continuous blooming, you can cut back during the growing season, staggering sections of your coreopsis flower patch weekly.

Pruning Tip

Looking for the best pruners for your coreopsis plant? We tested 10 top-rated pruners in our Lab to make sure your plant stays happy and healthy.

Propagating Coreopsis

Although perennial coreopsis are resilient plants, they don't tend to live more than three to five years. A decrease in flowering is a good signal that it's time to divide the plants (or to plant some new ones from seed) to propagate them. The best time to divide your plant is the spring or early fall—here's how:

1. Dig up the plant. First, carefully dig up a clump of a mature plant, leaving the roots as intact as possible.
2. Split into clumps. Use a sharp trowel to split the clump into smaller sections, ensuring several healthy roots are present on each section.
3. Replant your pieces. Replant the sections in a suitable growing site. Keep the new plants well-watered until they're established and show visible signs of growth, which can take several weeks.

How to Grow Coreopsis From Seed

Many coreopsis varieties can be grown from seed and often will reseed themselves in your garden. Start seeds indoors six to eight weeks before your area's projected last frost date, or directly plant seeds in your garden after your last frost.

Plant the seeds roughly 1/2-inch deep, and keep the soil lightly moist and warm. Seedlings should emerge in about two to three weeks, at which point you can put the seedlings by a sunny window and continue to keep the soil lightly moist.

Indoor seedlings must be slowly acclimatized to the outdoors by taking them outside for long stretches each day for about a week. Then, they're ready to be planted in the garden.

Attracts Pollinators and Wildlife

Birds and other wildlife love to snack on the seeds and nectar during the fall and winter, while bees and butterflies are drawn to the colorful blooms.

Potting and Repotting Coreopsis

Coreopsis can be grown in containers. If you start them in seedling containers, you can size them up and transplant them into larger ones. Coreopsis need containers at least 8 to 10 inches deep and wide with ample drainage holes. This plant's roots do not tolerate soggy, standing water.

After several years, if the plant's roots appear to grow out of drainage holes, it's time to divide the plant, as noted in the section about propagation. Once divided, replant the divided part in its container and backfill the rest with fresh soil.

Place the container in a spot with at least six to eight hours of full sun.

Summer Time

In the hot summer months, give more water than if it's in the ground. Containers heat up, and water evaporates from potting soil much sooner than in-ground plants.

Overwintering

Coreopsis are hardy plants. You don't have to give these plants winter protection, but if you have the perennial variety that returns annually, you can keep the roots healthy by ensuring the plant receive regular water up until the first frost. Cut back the stems down to the ground. Insulate the roots by layering 2 to 3 inches of mulch at the soil surface. Remove the mulch after the threat of frost is over.

Common Pests & Plant Diseases

For the most part, coreopsis plants grow problem-free. But they might fall prey to snails, slugs, mildew, and fungal diseases in wet seasons. Before turning to pesticides and fungicides, improve your plant's environment. Ensure it has plenty of air circulation to ward off pests and fungal problems. And note whether it's getting enough sunlight. Divide overgrown clumps where the centers aren't getting much air or light.

Pest to Watch

If you suspect snails or slugs, look underneath your plant's leaves at nighttime with a flashlight to see if they are there. Some other signs to look for are irregular holes.

How to Get Coreopsis to Bloom

One of the most critical factors in ensuring your coreopsis blooms each season is planting the flowers in an area with full sun—ample light for at least 6 to 8 hours. If you notice that your plant is struggling to bloom, too much shade may be to blame. If there's not a spot in your landscape that boasts six to eight hours of direct light a day, plant your coreopsis in a pot so you can move it around your lawn occasionally to "chase" the light.

It's important to reiterate that coreopsis does not need fertilizer. Giving fertilizer can cause the plant to grow disproportionally, making the plant put all of its energy into developing its stem and leaves and not enough energy into bud production. If your coreopsis could use a boost, add organic matter as compost to the soil instead.

Deadheading

Deadheading or removing the wilted bloom and stem can keep the plant blooming throughout summer and fall. The plant will not form new flower buds on a stem that held a faded flower.

Common Problems With Coreopsis

Coreopsis is an easy plant to care for. They are occasionally susceptible to bugs and diseases when their environmental factors are managed well. Ensure they get water, sun, and the correct soil when planting them.

Yellowing Leaves

Yellowing leaves are usually caused by overwatering or insufficient nutrition. Coreopsis does not require fertilizer unless it grows in poor soil; then, it might need a nutritional boost. If your plant has soggy soil, let it dry out before watering again. Instead of putting the plant on a regular watering regimen, only water it when the soil feels dry, about two inches under the surface.

The plant may have an iron or magnesium deficiency if you notice yellow patches between leaf veins. With a magnesium deficiency, the leaf's center yellows then the edges turn yellow last. Signs of an iron deficiency can appear as young leaves on tops, and branch tips turn yellow first.

A sulfur deficiency is primarily indicated when the newest leaves are entirely yellow. Your plant might have a potassium deficiency if the oldest leaf's edges turn bright yellow, but the leaf center remains green. A nitrogen deficiency causes the yellowing of the older inner leaves first; the rest of the plant shortly follows, moving outwardly with its yellowing.

Sunburned Leaves

Although coreopsis is a full sun plant, it can still get sunburned if it is indoors as a seedling and then is brought outdoors too suddenly without any acclimatizing. If the leaves suddenly turn yellow, white, or brown, they may have received too much sun too quickly. You can tell apart sunburn from other issues by turning over the leaf and inspecting the underside; sunburn is the likely culprit if it looks green and generally unaffected.

Gradually harden off the plants by exposing them to a small amount of direct sun each day before planting them in the ground or bringing their container outdoors permanently.

From: thespruce