Many perennial weeds require deep digging to winkle out their roots. It’s all too easy to leave the root fragments behind; dandelions and twitch are notorious for this. A glyphosate based herbicide such as McGregor’s Weed Out is a good choice for twitch since its active ingredient translocate through the plant to its root. But since twitch grass is dormant in winter, save the herbicide heavy artillery for the warmer months when the plant is growing actively.