With regards to the invasiveness of YI, IF the seeds are allowed to drop and germinate the plants will show up around the BOW and the discharge path of the BOW. The plants can show up hundreds of feet away from the BOW. I can confirm this from my own experience. As far as the plants spreading from existing plants, in my experience the plants tend to grow AWAY from the water's edge and not deeper into the water. At our pond after 15 years the plants' spread is all within 3' of the pond edges. In most places the plants are only one foot from the pond edge, growing away from the edge. The other native plants and grasses seem to slow the YI spread via their root system.
I'm not advocating YI is the best plant for every BOW. I'm just sharing that I much prefer YI to cattails that I've witnessed in our pond growing into depths of up to 6' of water, essentially choking the pond shallow areas. IMHO, YI can be part of a soil erosion solution. There are likely other preferable plants to YI. For our pond the YI are a positive. I just recently purchased and planted a couple dozen Pickerel Weed plants. I like adding color to the pond edges and watching the pollinators is nearly as enjoyable as observing the fish. I'm hopeful that the PW will add a different color to all the yellow of the YI. I was a bit surprised last evening to see a honeybee working the YI blossoms. I used to work for a beekeeper as a teen and found that blossoms with deeper shapes were typically not attractive to honeybees due to their mouth structure and focus on high nectar yield plants only. It was interesting watching the bee crawl deep into the blossom to extract the nectar. And, the plants will likely produce a lot of seeds this fall due to the pollination the bee is performing. I may remove most of the seed pods to limit the number of new plants next year.
RAH- thanks for sharing your experience to this thread. I'm new to the PB forum and others here have far more experience with all things pond. I value all the insight and experience.
