PlantFun
Plant Needs
Sunlight
Full sun exposure is required for abundant flowering; tolerates partial shade but will produce fewer blooms
Watering
Allow soil to dry completely between waterings; highly drought-tolerant once established
Temperature
Hardy to -20°C; withstands hot summer temperatures as long as soil drainage is adequate
Characteristics
- Leaf: Deeply lobed, spiny, gray-green basal leaves; smaller stem leaves with woolly undersides
- Flower: Round, metallic blue composite flower heads, 3–5 cm in diameter, clustered at stem tips
- Stem: Erect, branched, covered in fine white down
Care Guide
Watering
Water deeply when top 5 cm of soil is dry; avoid overwatering to prevent root rot
Fertilization
Apply balanced slow-release fertilizer once at the start of growth. Avoid over-fertilization, as it can cause leggy growth with fewer blooms
Eggshell powder topdressing：Crush clean, dried eggshells into fine powder; sprinkle 1–2 tbsp around the base of plants in early spring to boost calcium levels and deter slugsPruning
- Deadhead spent blooms to encourage extended flowering through early autumn
- Cut back all stems to ground level in late autumn after foliage has died back
- Thin overcrowded clumps every 2–3 years in early spring to improve airflow and reduce disease risk
Toxicity
Warning: this plant may be toxic.
Pets & Humans
Pets: ASPCA-verified non-toxic to cats; no reported toxicity
Humans: Non-toxic to humans; no known adverse health effects from ingestion or contact
Garden Uses & Culture
Culture: N/A
Usage: Ornamental garden plant; attracts bees, butterflies, and beneficial pollinators
