How to Kill Pond Iris

[TJeep_1999]

I'm afraid my Louisiana purple irises are now a permanent part of my pond. I tried to clear them out last fall, but short of moving some rather large rocks and tearing apart one side of my foamed in waterfall I was not able to get all the rhizomes removed. I got most of them, but they apparently liked the thinning b/c they have come back in force already this early spring. Short of tearing apart my rock structures is there a way I can safely kill them w/o harming the water chemistry and other plants?

 

[Lisak1]

I had a similar experience in my bog. I just kept pulling them out until they finally - mostly - gave up. I'll still find one or two popping up every year, but six or so years later and I feel like I finally won the battle.