How to Grow Ageratum (Floss Flower)

Ageratum's fluffy, long-lasting blooms in blue, pink, white, and bicolor make it a standout for borders, edging, and containers. Compact mounds flower all summer until frost.

Growing Conditions

• Zones: 5–10 (annual in all zones).
• Sun: Full sun (partial in zones 8+).
• Soil: Well-drained, enriched with compost or rotted manure. In pots, use multipurpose compost with drainage.

From Seed or Transplants

Start seeds indoors Feb–Mar in 3.5" pots at 70°F. Cover until germination (~1 week). Transplant to cell packs at two-leaf stage. Harden off after last frost. Space tall varieties 12–16", dwarfs 4–6".

Care

• Water consistently—avoid overwatering (causes root rot).
• Fertilize fortnightly or use slow-release at planting.
• Deadhead spent blooms for continuous flowering.
• Watch for spider mites and powdery mildew; treat with insecticidal soap or fungicide.

Bonus

Fragrant flowers attract bees and butterflies. Collect seeds by letting blooms dry on plant.

With minimal effort, ageratum delivers months of color and pollinator activity.