I think if I had planted PP by mistake, I think I would eradicate it and be done with it. My mom's neighbor did plant some, but it was never told how nasty it was. All I remember was how beautiful the flowers were in the spring. But then those neighbors moved and new ones moved in, and the PP was very soon gone.
As for me, the Biggest Plant Mistake, was:
I had bordered the west side of my garden, running north to south, with the large concrete blocks. I had found that weed seeds wash, that including clover and other type seeds that I didn't mind in the yard, but didn't want in the flower garden. I had already decided I would plant all the holes in the concrete blocks and my original intentions were things like creeping phlox, or good hardy short but slightly trailing plants.
Well, I had a pot full of tall bearded Iris seedlings that I didn't know what to do with, since at that moment I was out of space for planting. I had all the concrete block holes filled in with a combination of top soil and potting mix. Most still had not yet been planted. I decided spur of the moment to plant those baby Iris seedlings, (one per) in the holes. Who the heck would have been so wise to do such a thing?!.
Well, one thing I didn't realize was that the soil in the holes was going to drop considerably through the winter, leaving the hole only about half full. Time passed quickly, and before I knew it, those Iris were to a mature state. Trying to get well rooted mature Iris out of those concrete block holes just isn't easy. Now I certainly didn't have to deal with pricks from PP, but it's hard to get well rooted mature Iris out concrete block holes without destroying them. And I did not want to destroy them! . . . these were my babies. So I don't suggest planting Iris in concrete block holes unless you are absolutely certain there is no further settling of the soil to happen.
Still haven't got them all out of there. You can't exactly tell from this photo I took quickly today, as to the depth that the rhizome is down.
