i bought a plant that had lovely leaves, awful yellow flowers, but it became very invasive. SINACALIA...................... other plants I have that I have dug out clumps most years, are. Achillea 'the Pearl', Crocosmia lucifer, (which is allowed to stay in but in small clumps), also Elymus magellanicus, Kentucky blue grass. Carex Bronze Comans. Most of the hardy Geraniums especially Kaffir white. Persicaria firetail, and Southcombe white, Euphobia 'Fens Ruby', Darmera peltiphyllum quickly became a thug, but it is in an area where it looks ok. Sasa 4' bamboo. Rosa Rugosa, I have to prune out sections monthly. Rosa Bobby James, from a cutting five years ago, it is not only over my 30' workshop wall and roof, but is also going up into an ash tree and would be off down the field if I let it. Verbascum Chiaxii self seeds everywhere. Echinops self seeds, but the worst offender is a Cirsium rivulare, I grew from seed, hoping it would be cerise, turned out to be an awful wishy washy lilac. That has spread everywhere.