I've got some mostly isolated patches of Canada thistle in first year hay feilds.  this is a blend of Alfalfa, timothy, orchard grass, and alsike clover.  most places the hay has competed quite succesfully, and has a good stand along with the thistles.  The thistles were cut while most plants are budding, or just starting to flower.  IS there any hope that cutting at that stage will do enough damage that the remaining plants will have a chance next year?  I just checked for herbicide options, and it doesn't look promising.  Is there anything else I could try?  This is one cutting per year, with the cows taking the second cutting, however, I could cut the patches again later if it would serve any purpose.

Also, is there a safe quantity of Alsike clover to seed.  This land has enough low spots which don't grow alfalfa consistently, so I added about 1/3 lb/acre of alsike.  many places the stand is so thick that nothing else had a chance.  recommended rate is 5 to 10 lbs.