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, pink

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:
None required
Germination Time:
14–28 days
Notes:
Seeds germinate readily in spring without pretreatment. Light may improve germination rates.

The above propagation data sourced from Claude AI

ORGHPS Germination Guide: 15% germination rate; squeeze seeds to determine which are viable

Source: Ontario Rock Garden & Hardy Plant Society