Okay, here is my list of most despised invasive plants, most obnoxious first: 1) Violets. Like mints they spread through rhizomes (underground runners) and like a moist environment. Unlike mints the also spread profusely through seeds. But what makes particularly vicious spreaders is, that a portion of their seeds lie dormant for up to three years. So even if you let never another violet come to flower, they keep on springing up for three years. You have to pull them out, before they form that little knob at the base of the leaves, because immediately thereafter they start sending out rhizomes and you have to dig. 2) Mints. If you leave even a 1” section of the rhizomes in the ground, you will soon have another mint plant proudly surviving and spreading. If you leave a section smaller than 1 “ you will probably soon have… . During my childhood we lived near a small swampy area, which was teeming with mint, so much so, that you could harvest it with a scythe in places with only little contamination by other plants. So here are your choices as far as I can see them: • Dig up the infested area, sift thoroughly through the soil and remove by hand every little bit of rhizome you can find. Thereafter watch the area closely for any new plants piping up and remove every part of them. That is how I got rid of mine. • Easier would probably be, to spray the whole infested area with a weed killer and start anew. You could probably remove any plants you want to preserve prior to spraying. • This is a long shot, but you could try to deprive them of water. 3) Snapdragon. They are proliferate seeders and some of their seeds can also lie dormant for 3 or 4 years. 4) Ajuga. This shade lover can easily be contained with a 6” deep in-ground plastic barrier 5) Trifolium repens dark dancer, a dark four leaved clover ground cover. Spreads very rapidly by expansion of plant mass. Mine is contained between house, concrete sidewalk and concrete base of the outdoor heating & air conditioning unit. But I believe a six inch deep plastic edging would probably contain it. 6) Alyssium seed out in abandon, I got rid of them in our yard, but the neighbour had them at the property line and the seeds kept spreading over. An about 4’ wide barrier of dense ground cover blocked the ‘invasion’ out successfully. Most of the above plants I won’t even let on my compost. 7) Larger plants. For the other, larger plants like asters and bamboo I dig a hole in which I insert a plastic tub with the bottom cut out, top rim flush with the ground and plant them in there. That way the roots can expand below, but the rhizomes are contained. Oh yes, and there is horsetail. The same neighbour who was giving me alyssium (and dandelions*) in the front yard has a regular horsetail farm growing along the shore of a pond, which we both share. I got rid of mine, but they keep on invading underneath the fence. Because these pests have very little greens on them, they do not easily succumb to weed killers. It takes at least 5 or 6 applications of RoundUp in short intervals or to use the concentrate at $50.-/litre. The problem is, as much as you try to limit your spray, it takes so little of it, to kill everything around it too. Fortunately this man has now put his house up for sale and one other neighbour, who is interested in buying it has already asked me how to get rid of the horsetail, but he is now down south for the winter. :( * Dandelions do not bother me much, because they cannot penetrate the dense ground covers in our front yard.