GRRRRR the houttynia is just plain HATE for me. The former owners planted it. I worked for two years removing it. LONG story. Finally planted that bed last fall. It looks amazing this year. Last night I found that beast springing back up in one place. Quickly dug up the iris in that spot (thank heavens they are easily moveable!) and strained the soil for roots. I'll be back on daily patrol for it, ripping it sprouts or painting them with poison.
Oh and then I had that horrid smell on my all night despite wearing gloves when I removed it.
