Bull Thistle
Cirsium vulgare
Sunflower family
Where is it from?
- Bull thistle is native to Europe.
Where are you likely to find it?
- Grassy areas, open brush, pastures or along roads.
- Bull thistle can be found along in many prairies, dry pastures
and roadsides in the Redwood National and State Parks.
What makes it a "BAD" plant?
- Bull thistles produce millions of wind-dispersed seed
that rapidly colonize areas of disturbed ground.
- Although bull thistle is a biennial plant, infestations
persist for years in grassy areas to the exclusion of other
herbaceous plants due to the buildup of buried seed.
- Thistles make human and wildlife access difficult, if not
painful.
How do you get rid of it?
- The plants are cut off at ground level before the flower
heads turn purple to stop seed production.
- If heads have turned purple, they are cut off and placed
in bags. Once heads are purple, the seeds continue to
develop. If not bagged, these seeds would mature and blow
free. Some would germinate, spreading the plants.
- Dead plants can be left on site, but any purple flower
heads must be removed in bags and burned.
- Prevention is the most cost effective approach. After any
type of ground disturbance, quickly seed with desirable
species to minimize the opportunity for bull thistle
to become established.
What can you do to help?
- Report sightings. If in other parks, contact the
Superintendent. If in the Redwood National and State
Parks, notify the Vegetation Management branch at the
South Operations Center in Orick (707-464-6101, ext. 5282).
Tell them about the location of the plants so they can be
mapped for future work projects.
- To become even more involved in control of this and other
exotic species, sign up as a Volunteer
in Parks (VIP).
- CAUTION: Do not remove plants without permission
in writing or direction from a private land owner,
manager or, if on public lands, an agency official.
