Flowers

How to Grow Dusty Miller: Planting, Spacing, Care & Bloom

Quick answer

Start indoors 10 to 15 weeks before last frost (NC State). Transplant about 4 weeks before the frost-free date as a hardy annual (Illinois). NC State High poison severity — all parts toxic if ingested; can cause serious liver damage; wear gloves.

Dusty miller at a glance

PlantStart indoors: 15–10 wk before last frost; Transplant: 4 wk before last frost
SunFull sun; well-drained soil.
SpacingNC: silver mounds typically about 1–2 ft tall/wide depending on type.
Days to harvestFoliage ornamental; hardy perennial zones 7–10 (NC)
-16-15-14-13-12-11-10-9-8-7-6-5-4-3-2-1LF+1+2+3
■ Start indoors   ■ Plant out   ■ Harvest
Weeks relative to last frost (LF). Colored weeks show when our ZIP planner schedules each step.
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Updated

Safety: NC State poison severity High for Jacobaea maritima (syn). Senecio cineraria). “All parts of this plant are toxic if ingested. It can cause serious liver damage. Minor skin irritation can occur following contact… Protective clothing and gloves are recommended.” Toxic principle: pyrrolizidine alkaloids. Poison parts include bark, flowers, fruits, leaves, roots, and sap/juice. Problem for cats, dogs, horses, and children. Not medical advice. (NC State Jacobaea maritima)

Dusty miller (Jacobaea maritima / Senecio cineraria) — silver foliage annual north; hardy perennial zones 7–10 (NC).

Dusty miller foliage
Dusty miller (Senecio cineraria). Photo: H. Zell, Wikimedia Commons, CC BY-SA 3.0 (resized).

Sourced from university extension guides. For dates where you live, use the ZIP planting planner.

Planting timing

NC State: “You can start the seeds indoors 10-15 weeks before the last frost date.” (NC State Jacobaea maritima) Illinois Extension: dusty miller among hardy annuals that tolerate light frost — “These can usually be planted about four weeks before the frost free date in your area.” (Illinois annuals) Planner: Start indoors last frost −15 to −10; Transplant last frost −4. Wear gloves when handling.

Depth and spacing

NC: silver mounds typically about 1–2 ft tall/wide depending on type. Needs light to germinate (MU). Space for air flow.

Sun, soil and water

Full sun; well-drained soil. Grown for foliage; wet soils invite rot.

Care

Shear if leggy. Handle with gloves (NC). Often treated as an annual north of zone 7.

Bloom

Grown mainly for silver foliage; small yellow flowers may appear — many gardeners shear them to keep the foliage show.

Pests and diseases

Usually few insects; watch rot in poorly drained sites. Cultural drainage first.

Related: ZIP planner · organic pest control

Frequently asked questions

When do I start dusty miller?

10 to 15 weeks before last frost indoors (NC); set out about 4 weeks before frost-free date (Illinois).

Is it poisonous?

Yes — NC State High severity; pyrrolizidine alkaloids; wear gloves; do not ingest.

Perennial or annual?

Hardy perennial zones 7–10 (NC); often grown as an annual farther north.

Sources