Large-flowered coreopsis
Coreopsis grandiflora · Asteraceae
📷 Alois Lunzer (1840-?) · Public domain
The gardener's calendar
Large-flowered coreopsis is in full bloom: enjoy it, watch watering in hot weather and let spent flowers feed pollinators before pruning.
ID card
- Family
- Asteraceae
- Type
- Perennial herbaceous plant
- Adult height
- Approximately 45 cm
- Flowering
- May to September
- Exposure
- Full sun
- Water requirement
- Low
- Hardiness
- Very hardy
- Foliage
- Deciduous
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability high.
Expert tips
The key tip
Large-flowered Coreopsis produces even more flowers when slightly water-stressed: a poor, well-draining soil promotes flowering much better than rich soil.
The common mistake
People enrich it with compost or fertilizer 'to make it flower better', it becomes lush and leafy but flowers poorly; it's a plant of scarcity, not abundance.
The pro's trick
Divide the clumps every 2-3 years in April.
Seasonal watch
August-September in very rainy summers: it can rot at the collar if the soil stays waterlogged.
Care
Exposure
Large-flowered Coreopsis demands full sun for generous, colorful blooming. Install it in a location receiving at least 6 hours of direct sunlight daily. Insufficient exposure slows growth and considerably reduces flower production.
Watering
This plant tolerates drought well once established. Water regularly during the first year to promote rooting, then gradually space out waterings. In summer, watering every two to three weeks is sufficient; reduce further in autumn and winter.
Soil
Coreopsis appreciates well-drained soil, even poor or sandy. Overly rich or wet soil can promote rot. Improve drainage if your soil is clayey by adding sand or gravel.
Pruning and maintenance
Deadhead regularly (remove spent flowers) to extend flowering until frost. In late winter or early spring, cut back the clump to 10-15 cm from the ground to encourage vigorous growth. This pruning rejuvenates the plant and maintains a compact form.
Fertilizer
Coreopsis requires little nutritional input. Light fertilization in spring is sufficient; excess fertilizer makes the plant too soft and reduces flowering. Prefer a balanced or nitrogen-poor fertilizer if needed.
Health and problems
This plant is very robust and rarely susceptible to disease. In excessively humid conditions, watch for powdery mildew or root rot. Ensure good drainage and air circulation to prevent these issues.
Did you know?
Large-flowered Coreopsis originates from prairies and dry terrain of the United States, where it blooms abundantly in xerophilic conditions. Its name derives from the Greek 'koris' (bedbug) and 'opsis' (appearance), as its seeds resemble tiny bedbugs. This robust plant has become a favorite of modern gardeners for its reliable flowering, hardiness, and incredible ability to rebloom all summer with simple regular deadheading.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
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Tips generated and checked by Viridia — adapt them to your local climate.