When i bought my house a year ago i inherited a large area of block paveing on my driveway.The joints have been pointed or brushed in with a fine sharp sand, and as you can appriciate digging the joints out is takeing forever.I have done a search and i have found that if i use Simazine pathclear this should do the trick. Would it still be best to try and dig out the roots or is this enough for six months.