How to Grow Sweet William (Dianthus barbatus): Fragrant Biennial for Cottage Gardens

How to Grow Sweet William (Dianthus barbatus)

Sweet William is a classic biennial (often grown as annual) from Europe, forming 12–24 inch mounds of fragrant, clustered blooms in white, red, pink, crimson, scarlet, purple, and bicolors in spring of its second year. Compact habit suits containers, windowsills, and front-of-border. Good cut flowers for small vases. Named for William the Conqueror, Saint William of York, or Prince William Augustus—take your pick.

Propagation

Sow seeds indoors 6–8 weeks before last frost for first-year bloom, or direct-sow. Cover ⅛ inch. Transplant after frost, 6 inches apart. Also roots from cuttings/division. Germinates 10–15 days.

How to Grow Sweet William

• Light: Full sun; tolerates light shade.
• Soil: Rich, loose, well-drained.
• Water: Keep moist to slightly dry; water weekly in drought.
• Fertilizer: Monthly balanced feed.
• Maintenance: Mulch for tidiness. Deadhead for rebloom.

Bloom Time

Spring to summer.

Pests & Diseases

Nematodes possible—treat with specific nematicide. Fungal issues rare—fungicide if needed.