Water hyacinths will also work well in a bog type situation and are great in aiding filtration because the roots are so fibrous.
I have tried some in the pond for the koi to play with - the WH get so beaten up by the koi! WH would never last long in my pond if I just had them floating. They also have a way of finding their way into my skimmer.
I do buy them every year - but I also compost them each in the fall as well. It does not take much for the frost to do them in. If I buy them too early, I have to protect them as some of the cool May mornings can do them in as well.
