Creeping Thistle

there is a weed killer that attacks the hole plant from the inside i think its called systemmick but i cant spell as you will be chopping it down for ever.normal weed killer will just kill what you can see which is pointless in the long run.i think you have to actualy let your shoots grow a bit as you spray or paint depending on how close your other plants are.it allows more poisan to enter the plant and in its flush of growth now the sap for want of a better word is surging through your plant the most.i hope ive helped .im sure a a better gardener will explain far better than i have.take care bye for now.

roundup is as good as any and as np says it is systemic. I use it especially in the late summer early autumn as the weedkiller is translocated to the underground rhizomes and does its job over the winter. works on bind weed too.