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Thistles - act in May and June

Posted: Sat Jun 19, 2021 2:09 am
by Amy
I have put links to some pdfs in Resources Recommended PDFs viewtopic.php?f=74&t=241

Copied extracts below of points which particularly struck me and the emphasis is mine not theirs:

Prevention .. the aim is to maintain a well‐managed perennial sward without gaps, avoid overgrazing (especially in winter) and poaching which opens up gaps in the sward into which thistles, dock and ragwort can spread. ....

only Creeping Thistle and Spear Thistle ... require control. ....
 Cutting .... with a scythe or strimmer.
Timing is very important with the cut being done when the flower is still in bud but turned purple.
 Digging out
 For Spear Thistle use a spade to dig out the root and destroy the rosette.
 This should not be used for Creeping Thistle as it will only help to spread the plant.

.....
• If topping only once, top at the flower bud stage so as not to encourage coppice regrowth

Pulling:
• Pulling is more effective than cutting and avoids shoots developing at the base of the stem

Defra: Weeds - Identification of Injurious Weeds (PB4192) has pictures of spear thistle. Discusses difference to other thistles. The side bar menu will also take you to creeping thistle.
http://adlib.everysite.co.uk/adlib/defr ... 4&id=99312

Re: Thistles - act in May and June

Posted: Mon Jun 21, 2021 4:33 pm
by jennymsaunders
Why is Spear Thistle injurious please. I can't see where is says on the Defra ID link.

Re: Thistles - act in May and June

Posted: Mon Jun 21, 2021 11:19 pm
by Amy
Hi Jenny, I'm not a farmer, but spear thistle must have been a huge problem for farmers in 1959 to be included in the Injurious Weeds Act. I suppose that was the time, after the War, when farmers were encouraged to massively increase production, which led to so many changes.. anyway I found this:

"C. vulgare is an invasive weed in many parts of the world, notably Australia, Canada and the USA, and has the potential to compete with many crops and natural species and displace them from their natural habitats. Since this species can tolerate adverse environmental conditions and adapt to different habitats, it continues to spread and occupies new areas despite the control measures applied. High seed production, variation in seed dormancy, and vigorous growth habit make this species a serious invader. It competes with other species in pastures, rangelands and agricultural fields and causes both wool fault and physical injury to animals. It is difficult to eradicate entirely from an area due to its high seed production, variable life form and sequential germination pattern."
https://www.cabi.org/isc/datasheet/13631

and the thistle spines can get lodged in the sheep fleece, I think = the wool fault referred to above,

and apparently lambs prick their mouths on it when grazing, get the orf virus, and their mothers get mastitis
https://www.fwi.co.uk/livestock/thistle ... -orf-cases

(Its seeds do seem to colonise any damp/wet/dry/bare/boggy ground, and they can be seen floating en masse in the wind, but the seedlings are easy to grub out as long as you can catch them early, so much less painful than tackling a mature 2nd year plant.)

No, the original pdf I linked to on the other page doesn't explain.

Re: Thistles - act in May and June

Posted: Sun Jun 27, 2021 1:38 pm
by jennymsaunders
Thanks Amy - that is very interesting. My farmer neighbour doesn't appear to be bothered about spear thistle, it is allowed to grow in his 'set aside' strips in fields that are sometimes used for sheep. However my dog doesn't like it much when he steps on it, so I can see it might be a problem for sheep. It is a very beautiful purple thistle flower head when it eventually flowers, so I think I will continue to leave a few in a corner.