Bull thistle
Cirsium vulgare · Asteraceae
The gardener's calendar
Ideal time to plant bull thistle: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Blooming
- July to September
- Adult size
- 0.6 to 1.5 m in height
- Growth
- Fast
- Hardiness
- Very hardy (down to -15 °C)
- Origin
- Europe, temperate Asia
- Soil type
- Well-drained soils, undemanding
Care
Watering
Common thistle is undemanding for water once established. Water moderately during prolonged dry spells, especially in summer. Avoid excess moisture which promotes rot.
Exposure
This plant appreciates a full sun location for optimal flowering. It tolerates semi-shaded areas, but its vigor is reduced there.
Soil
Thistle adapts to most soils, including poor and stony ones. Well-drained soil is recommended to prevent waterlogging. Adding compost at planting time helps establishment.
Pruning and deadheading
Deadhead spent flowers regularly to extend blooming and limit self-seeding. In late autumn, cut stems back to ground level. You can also remove plants entirely after the first year if desired.
Fertilizing
Common thistle doesn't require regular fertilization. An application of compost or organic matter in spring is sufficient. Avoid excessive nitrogen fertilizers which promote foliage at the expense of flowers.
Diseases and pests
This species is robust and rarely affected by diseases. Occasionally watch for aphids and spider mites in hot, dry weather. Good air circulation and moderate humidity limit fungal problems.
Did you know?
Common thistle, also called woolly thistle, was long considered an invasive weed in agriculture, but it plays a crucial ecological role: its violet-purple flowers are a precious source of nectar for butterflies and wild bees, particularly late in the season. In permaculture and wild gardens, it's now appreciated as a remarkable honey plant.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
Add this plant to my garden →Plants from the same family
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- SneezewortAchillea ptarmica
- Canadian goldenrodSolidago canadensis
- WormwoodArtemisia absinthium
Tips generated and checked by Viridia — adapt them to your local climate.