I is for Invasive Iris on the A to Z Blogger Challenge. Ihe iris in question here is the yellow flag, Iris pseudacorus, which I planted at the edge of our Frog Pond nearly 20 years ago. It didn't actually succeed there, which is amazing, but before it died it sent seeds up to our Sunken Garden which is very wet. I have been trying to destroy this plant for years, letting the little grandsons loose with clippers…