What are calendula's main disadvantages?
Written by
Kiana Okafor
Reviewed by
Prof. Martin Thorne, Ph.D.Calendula is beneficial, but there are known limitations to calendula that every gardener should be aware of. Knowing these limitations facilitates the preparation of preventative strategies that can lead to success in growing calendula, even when the calendula are susceptible to some environmental conditions and growth habits.
Disease Vulnerability
- Powdery mildew in humidity: Improve airflow with proper spacing
- Botrytis in wet conditions: Water at soil level only
- Root rot prevention requires well-draining soil mixes
Environmental Stressors
- Heat above 85°F causes flower reduction: Use shade cloth
- Frost damage below 28°F: Apply protective mulch layers
- Wind protection needed for tall varieties in exposed areas
Growth Management
- Control self-seeding with deadheading before seed formation
- Prevent volunteer spread with border edging around beds
- Manage leggy growth through regular pinching techniques
To prevent mildew, careful consideration needs to be given to environmental management. Proper spacing can help ensure air circulation. Keep water off the overhead when possible, especially in humid conditions. Choose resistant varieties and apply preventative baking soda sprays early in the growing season.
Tackle the short vase life of blooming calendula. Harvest flowers in the early hours, blooms with the closure of the center. Place stems in warm water with floral preservatives immediately after harvest. Change the water daily and re-cut the ends of the stems to prolong the display life for up to 5-7 days.
Readiness to manage self-seeding behavior appropriately. Before the seedheads' heads dry up and scatter, collect them all. Select areas for calendula to contain self-seeders. Allow naturalized growth to occur in wildflower gardens; allowing it to spread continues to support the ecosystem.
Read the full article: How to Grow Calendula: Complete Guide
