PlantFun
Plant Needs
Sunlight
Full sun preferred; tolerates light afternoon shade in hot, arid regions to prevent leaf scorch
Watering
Water deeply when the top 5 cm of soil is dry; drought-tolerant once established, avoid waterlogged soil
Temperature
Hardy to USDA zones 4-9; tolerates extreme winter cold and summer heat with proper drainage
Characteristics
- Leaf: Narrow lanceolate leaves arranged oppositely; smooth medium green with prominent lateral veins
- Flower: Clustered umbels of pale green star-shaped blooms with hooded corollas
- Stem: Erect, hairy stems that exude toxic milky sap when damaged
Care Guide
Watering
Keep soil evenly moist during active growth; avoid overwatering to prevent root rot
Fertilization
Optional light, balanced organic feed once at emergence. Fertilization is rarely needed in native soil conditions
Crushed eggshell topdress：Crush dried eggshells into fine powder; sprinkle lightly on soil surface in early spring to boost calcium levels without overfeedingPruning
- Remove spent flower heads to encourage reblooming and limit self-seeding if desired
- Cut back dead foliage to ground level in late fall to reduce overwintering pest habitat
- Thin crowded clumps every 2-3 years in early spring to improve airflow and reduce competition
Toxicity
Warning: this plant may be toxic.
Pets & Humans
Pets: ASPCA: Toxic; contains cardiac glycosides that can cause severe cardiovascular and gastrointestinal symptoms
Humans: Contains cardiac glycosides; ingestion of large amounts may cause cardiac issues and gastrointestinal distress
Garden Uses & Culture
Culture: N/A
Usage: Primary nectar source for monarch butterflies; supports native pollinator populations in wild meadows
