- Plants form a deep branched taproot in the first year providing good anchorage into the ground.
- Seeds are air borne and readily germinate in warm weather. Each seed head can produce around 100 seeds.
- Although the species can be invasive, seeds are an important food source for a range of farmland birds including linnets and finches.
- Spear thistle is a tall biannual species, the flowering stem typically grows to 30cm – 1m in height usually in the second year.
- Leaves are deeply divided with lobes terminating in a sharp spine. The upper surface of the leaf is rough and hairy.
- Flowers heads appear from July to September with lilac-purple florets.
- Seeds have a downy pappus which aids wind dispersal. The flower stems die back after producing seed.
Spear thistle can be successfully treated with herbicide, applications are most effective whilst the plant is actively growing between April and October. Established infestations may require treatment over a number of years to ensure the seed bank is depleted.
Infestations can be weakened by repeated cutting over a number of years before the plants produce seed.
If you have concerns over Spear thistle on your land, if you are unsure of your legal responsibilities, or if you would like a quotation for control, please contact one of our specialist surveyors. Treatment costs start from £380.00 + VAT.