A couple of years ago I attempted to identify the native plants growing around our pond. With my younger brother's help, we identified dogbane, boneset, joe pye, ironweed, goldenrod, purple aster, white aster and swamp milkweed. During the identification process he strongly recommended allowing the swamp milkweed to propagate for the Monarchs. Now knowing what to look for, sure enough, I was finding a few of the familiar Monarch caterpillars munching the swamp milkweed leaves. And the butterflies extracting nectar from the flowers. So we've had a native growth of the plants for a long time, but I didn't use much discretion when it came to trimming the pond edges. Now I let the swamp milkweed grow and sacrifice it's flora to the Monarchs. My brother also encouraged my propagation of the Joe Pye weed both for aesthetics and for the pollinators.
When the native plants are allowed to grow to 3' and higher, I've found the plants to also act as windbreaks for catching leaves blowing from nearby trees. While I can't prove my theory regarding soil erosion reduction, I suspect that the YI and native plants are reducing the soil wash during heavy downpours. Along with this natural plant barrier, I've started reseeding the yard that's sloped to the pond too. Now if I can just stay on top of the occasional muskrat invasion.... I digress....
So count me in for maintaining and propagating swamp milkweed around the pond. Many small ponds in our area are mowed and maintained right to the water's edge. IMHO, however, I think allowing native plants to grow around the pond has many advantages for the fish, insects and wildlife. Just a matter of personal preference and philosophy. We're blessed to have the pond and if we can manage in a way to help the environment (and native species), it's a win-win.
