For years, I have had monkey grass growing at the edge of my yard. It is dark green, grows in clumps, and has a blade width of about 1/4 inch. However, I also have another type of monkey grass with a much slimmer blade width and the root system consists of tiny thread-like roots all intermeshed and rolled into a ball. You cannot pull it up with your hand but have to dig it out, and it is tough. It does not stay in clumps but single plants are growing all over. Can you tell me what this is? I'm digging it up and throwing it away because it is getting into other plants where I don't want it and growing all out into the yard. Thank you.
Well it sounds like you have some creeping liriope (L. spicata) mixed in with your clumping type. This kind is quite aggressive and better left to fill in large empty spaces of the landscape. You can spot treat this invading monkey grass with Round-up or hand dig it out.