Canterbury farmers asked to report sightings of Saffron Thistle
Canterbury farmers are encouraged to look out for and report sightings of the yellow flowering thistle, Saffron Thistle (Carthamus lanatus) to Environment Canterbury.
The Biosecurity team at Environment Canterbury is working with the farming industry to eliminate Saffron Thistle from the region. Saffron Thistle competes with pastures species forming large dense stands and, when it gets established, can reduce stock carrying capacity, which in turn impacts production. Its sharp spines can cause injuries to the eyes and mouths of stock and get stuck in wool.
Environment Canterbury Resource Management Principal Biosecurity Advisor Laurence Smith said, “We ask anyone who suspects they have Saffron Thistle to let us know as soon as possible. It will be flowering and easily identifiable with its yellow flowers from December to April. We want to eliminate it to protect their property, as well as to protect the rest of the region, which is at risk of it spreading further afield.”
Saffron Thistle is currently only known in a few localised areas of Canterbury. This gives the region a good opportunity to eliminate it before it becomes established and widespread like scotch and nodding thistles.
“Biosecurity staff have been monitoring and controlling all known Saffron Thistle sites in our region since the 1970s. Last season, we controlled around 22,000 plants over 23 known properties in the region,” said Smith.
“We need to do more searching to make sure we are aware of all sites. Landowners and public are an important part of finding new sites. With 14 biosecurity staff and 45,346 sq km of land in Canterbury to cover, every extra set of eyes that report suspected pests, helps to protect our region’s economy and biodiversity.”
How to identify Saffron Thistle
Saffron Thistle is identified by its yellow flowers with purplish veins (most other thistle species have pink/purple flowers). It flowers from December to April, growing up to 1m tall. The leaves are glossy, dark green, with sharp-tipped spines, and grow out from a centre point to form a rosette. From late spring to early summer, a single stem grows from this rosette. Over time, the rosette leaves disappear and the stem divides into many branches with flowers. Seeds germinate in autumn.
How Saffron Thistle can spread
Saffron Thistle spreads via stock, soil contaminated machinery and footwear, and contaminated feed. Its seed is heavy, so it mostly drops close to the parent plant, however the whole plant can also break off at the base and be blown for long distances.
Seed remains dormant in the soil for at least eight years, and seed buried more than 10mm deep may remain dormant until cultivation, or other soil disturbances, bring it to the surface.