Whorled Tickseed
Coreopsis verticillataUSDA | Grow Zone
3-9Outdoors all year in zones 3 to 9. Anywhere colder, keep it as a houseplant.
- Light
- Full sun, 6-8 hours
- Water
- Every 1-2 weeks
- Humidity
- 40-60%
- Temperature
- 65-75°F (18-24°C)
- Difficulty
- Beginner
- Growth
- Moderate
- Mature size
- 2-3 ft tall, 1-2 ft wide
Coreopsis verticillata, commonly known as Whorled Tickseed, is a vibrant perennial native to North America. With its cheerful yellow flowers and resilience, it is a favorite among gardeners for adding color and attracting pollinators.
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Ideal temperature
65-75°F is where it grows fastest.
Spacing and harvest
- Mature size
- 2-3 ft tall, 1-2 ft wide
- Plant apart
- 12-24 in
- Frost
- Hardy: survives frost
Everything it needs
9 essentials at a glance
Watering
Coreopsis verticillata prefers well-drained soil and should be watered deeply but infrequently.
Water every 1-2 weeks during the growing season, allowing the top inch of soil to dry out between waterings. In hot, dry weather, increase frequency but avoid waterlogging. Signs of over-watering include yellowing leaves and root rot, while under-watering may cause wilting and browning leaf edges.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
Ideal placement is in a south or west-facing garden bed. While it can tolerate partial shade, flowering may be reduced in lower light conditions.
Soil
Coreopsis verticillata prefers sandy or loamy soil with a pH range of 6.0 to 7.0.
Ensure excellent drainage to prevent root rot, and consider using a potting mix designed for perennials or a mix of compost and sand for container planting.
Humidity
This plant prefers moderate humidity levels, ideally between 40-60%.
To increase humidity, mist the plant or place a humidifier nearby. Signs of humidity stress include leaf curling and browning tips.
Temperature
The ideal temperature range for Coreopsis verticillata is 65-75°F (18-24°C).
It is hardy in USDA zones 3-9, tolerating cold down to -30°F (-34°C) and heat up to 90°F (32°C). During extreme heat, provide some afternoon shade to prevent stress.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10, applying it every 4-6 weeks during the growing season.
Reduce fertilization in late summer and fall. Signs of nutrient deficiency include stunted growth and yellowing leaves.
Pruning
Prune Coreopsis verticillata in early spring before new growth begins.
Use sharp, clean pruning shears to remove dead or damaged stems. Deadheading spent flowers throughout the blooming season encourages more blooms and prevents self-seeding.
Repotting
Repot Coreopsis verticillata every 2-3 years or when it becomes root-bound.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes and stunted growth. To repot, gently remove the plant from its pot, loosen the roots, and place it in fresh soil.
Propagation
Coreopsis verticillata can be propagated through division or seeds.
For division, do this in early spring or fall by carefully separating the root clumps and replanting them. For seed propagation, collect seeds in late summer and sow them in a seed tray, covering lightly with soil. Keep moist until germination, which typically occurs in 2-3 weeks.
When it's unhappy
Yellow leaves
Why it happens
Over-watering or nutrient deficiency.
How to fix it
Check soil moisture levels and adjust watering schedule. Fertilize if nutrient deficiency is suspected.
Root rot
Why it happens
Poor drainage or excessive watering.
How to fix it
Ensure proper drainage and reduce watering frequency. If root rot occurs, remove affected roots and repot in fresh soil.
Wilting
Why it happens
Under-watering or extreme heat.
How to fix it
Water deeply and regularly, especially during hot weather. Provide some shade during peak heat.
Powdery mildew
Why it happens
High humidity and poor air circulation.
How to fix it
Improve air circulation around the plant and apply fungicide if necessary.
Stunted growth
Why it happens
Nutrient deficiency or root-bound conditions.
How to fix it
Fertilize appropriately and consider repotting if the plant is root-bound.
Care through the year
Spring
In spring, prune back any dead stems and apply a balanced fertilizer to encourage new growth. Monitor for pests and diseases as new growth appears.
Summer
During summer, ensure consistent watering, especially in dry spells. Deadhead spent flowers to promote continuous blooming.
Fall
In fall, reduce watering as the plant prepares for dormancy. Cut back spent foliage after the first frost to tidy the garden.
Winter
In winter, protect the plant from extreme cold by mulching around the base. Avoid excessive watering during dormancy.
Toxicity & Safety
Coreopsis verticillata is non-toxic to pets and children. It is safe to have around cats and dogs, with no known adverse effects from ingestion.
Good to know
Why are my Coreopsis verticillata leaves turning yellow?
Yellow leaves can indicate over-watering or a nutrient deficiency. Check the soil moisture and adjust your watering schedule accordingly.
How often should I water my Coreopsis verticillata?
Water every 1-2 weeks, allowing the top inch of soil to dry out between waterings. Adjust frequency based on weather conditions.
What type of soil does Coreopsis verticillata need?
This plant prefers sandy or loamy soil with good drainage and a pH between 6.0 and 7.0. Avoid heavy clay soils.
How can I propagate Coreopsis verticillata?
You can propagate it by division in spring or fall, or by sowing seeds collected in late summer. Keep the soil moist during germination.
What should I do if my Coreopsis verticillata is wilting?
Wilting may be a sign of under-watering or extreme heat. Water the plant deeply and consider providing some afternoon shade.
When should I prune my Coreopsis verticillata?
Prune in early spring before new growth begins. Deadheading spent flowers throughout the season will encourage more blooms.
Is Coreopsis verticillata toxic to pets?
No, Coreopsis verticillata is non-toxic to pets and children, making it a safe choice for gardens with animals.
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