I went through one poison after the other and nothing would kill my scourge, Houttuynia. Then a friend recommended the PI Killer so for $8.99 I tried it and they were dead the next day. I kept watch and they did not resprout. Wish I had known about it 8 years ago and saved myself hundreds of daylilies and months of daily digging for years.
When I did run out I tried some concentrate Weed B Gon - nothing. It didn't even weaken the Houttuynia.
