Please can someone help me! I had this large bush in my garden with large purple flowers on it a bit like a thistle. We dug it out last year and now we have tons of shoots popping up all over the area that it was and a bit further with the same leaves. Ive tried weedkillers and digging it out but it seems to have quite tubular roots which break easily and must be so deep as ive practicallg dug up the entire area! Please can someone tell me what it is and how to get rid!