Coreopsis (Tickseed) Care: Growing Cheerful Sun-Lovers
Coreopsis, commonly known as Tickseed, lights up the garden with its profusion of cheerful, daisy-like flowers, typically in sunny shades of yellow, gold, orange, pink, red, or bicolors. These plants are valued for their incredibly long bloom season – often flowering from late spring right through summer and into fall with proper deadheading. Most are easy to grow, tolerant of heat and humidity, relatively drought-tolerant once established, and attract butterflies.
Common Types of Coreopsis
Coreopsis includes annual and perennial species, with many popular cultivars:
Perennial Coreopsis
- C. verticillata (Threadleaf Coreopsis): Fine, airy foliage; small yellow flowers; spreads; drought tolerant, reliable (Zones 3-9). Examples: 'Moonbeam', 'Zagreb'.
- C. lanceolata (Lanceleaf Coreopsis): Lance-shaped leaves; larger yellow flowers; can self-seed (Zones 4-9).
- C. grandiflora (Large-flowered Tickseed): Larger yellow flowers (sometimes double); often short-lived (Zones 4-9). Example: 'Early Sunrise'.
- Modern Hybrids: Offer different colors (pinks, reds); longevity varies. Examples: Li'l Bang™ series, Uptick™ series.
Annual Coreopsis
- C. tinctoria (Plains Coreopsis / Calliopsis): Fine foliage; flowers yellow with maroon centers or solid red/orange; readily self-seeds. Excellent for meadows.
- Cultivars of other species often grown as annuals.
Planting Coreopsis
These sun-lovers are straightforward to plant.
When to Plant
- Spring: Best time, after the danger of frost has passed. Allows them to establish before blooming heavily.
- Fall: Possible in milder climates, but spring planting is generally preferred.
Ideal Growing Conditions
- Light: Full sun (6-8+ hours daily) is crucial for best flowering and sturdy growth. Tolerates very light shade but flowering will be significantly reduced.
- Soil: Well-draining soil is essential. They tolerate a wide range of soil types, including poor, sandy, or rocky soil, as long as drainage is good. Avoid heavy, constantly wet clay. Average fertility is best; overly rich soil can cause floppy growth.
- Spacing: Space 12-24 inches apart, depending on the mature size of the variety, to allow for good air circulation.
Planting Technique
Sun and drainage are the priorities.
Loosen the soil. Amend heavy clay to improve drainage with compost and/or grit if needed. Avoid making the soil too rich.
Dig a hole roughly the same size as the root ball.
Gently remove the plant from its pot. Place it in the hole so the top of the root ball is level with the surrounding soil.
Fill the hole with soil, firming gently. Water thoroughly to settle the soil.
Watering Coreopsis
- Water regularly after planting until established (first few weeks).
- Once established, Coreopsis are quite drought-tolerant. Water deeply but infrequently, primarily during extended hot, dry periods.
- Allow the soil to dry out somewhat between waterings. Avoid overwatering, which can lead to root rot or fungal diseases.
Fertilizing Coreopsis
- Generally not necessary or recommended. Coreopsis thrives in average to lean soil.
- Fertilizing, especially with high nitrogen, encourages leggy growth and reduces flowering.
Maintenance for Continuous Bloom
Deadheading / Shearing (Essential!)
- Key to long bloom season: Regularly removing spent flowers prevents seed formation and encourages the plant to produce more buds.
- Method 1 (Individual Deadheading): Snip off individual spent flowers and their stems back to a main stem or leaf node. Tedious for prolific bloomers.
- Method 2 (Shearing): Once the initial heavy flush of blooms starts to fade (mid-summer), shear the entire plant back by about one-third to one-half. This removes most spent flowers and stimulates a fresh wave of growth and blooms. Threadleaf Coreopsis (C. verticillata) responds particularly well to shearing.
Division (Perennial Types)
- Perennial Coreopsis can become crowded or less vigorous after 2-3 years.
- Divide clumps in early spring just as new growth emerges, or in early fall. Dig up the clump, separate it into smaller sections (each with roots and shoots), and replant immediately. C. verticillata spreads by rhizomes and is easily divided.
Cleanup
- Cut back dead stems of perennial types in late fall or early spring before new growth begins.
Troubleshooting Common Problems
Coreopsis are relatively trouble-free when sited correctly.
Powdery Mildew / Leaf Spot
Symptoms and Management
- Fungal diseases causing white coating (mildew) or spots on leaves, especially in humid weather or overcrowded conditions.
- Prevention/Control: Ensure full sun and good air circulation (proper spacing, division when needed). Water at the base. Remove affected leaves. Often cosmetic; resistant varieties are available.
Crown Rot
Symptoms and Management
- Plant base rots, stems wilt and collapse.
- Cause: Poor drainage, overly wet soil.
- Prevention: Plant in well-draining soil. Avoid overwatering.
- Treatment: Usually fatal. Improve drainage before replanting.
Leggy Growth / Reduced Flowering
Possible Causes and Solutions
- Insufficient Sun: Needs full sun.
- Overly Rich Soil: Prefers average to lean soil.
- Lack of Deadheading/Shearing: Essential for continuous bloom.
Conclusion
Coreopsis are cheerful, hardworking perennials and annuals that bring months of sunny color to the garden with minimal care. Their tolerance for heat, humidity, and drier soils makes them valuable additions to borders, containers, and wildflower plantings. Provide full sun, good drainage, and regular deadheading or shearing, and these bright bloomers will reward you with a long-lasting display that delights both gardeners and butterflies.
