I know that Bearded Iris must be planted with half their rhisome exposed. I have a bed that keeps getting over run with Bishop's weed no matter how much I pull it out. I like it as a ground cover and want to keep it since this is a difficult spot. I've planted several dozen daylilies in this bed, because I figured they won't be choked out by the Bishop's weed. I'd like to add some Bearded Iris, but was wondering if the Bishop's Weed will prevent the irises from blooming since the foliage will likely cover the rhisomes for the most part. I wasn't sure if the rhisome needed to be exposed so it got direct sun, or if their was another reason. Anyone have experience growing Bearded Iris with a ground cover that can cover the rhisomes from time to time?