Stemless Thistle
Onopordum acaulon
- Native to:
- Algeria, France, Morocco, Spain, Tunisia
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Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Onopordum
- Species:
- Onopordum acaulon
- USDA Symbol:
- ONAC2
Growth Characteristics
- Life Cycle:
- Annual | Biennial
- Growth Habit:
- Forb/herb
- Height:
- 30 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- High
- Bloom Months:
- jun,jul,aug
- Bloom Colors:
- purple
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies
- Deer Resistant:
- Yes
Soil Requirements
- Soil Type:
- dry, sandy, well-drained soil
- pH:
- 6.0 - 8.0 (neutral to slightly alkaline)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- native to Mediterranean regions; prefers open, sunny areas
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 14–30 days
- Notes:
- Seeds germinate readily after cold stratification; sow in spring.
ORGHPS Germination Guide: 15% germination rate; squeeze seeds to determine which are viable