Schroeder,
In our neck of the ponds, Pickerel Weed (Pontederia cordata) is our number 1 species we recommend pond owners to establish in their ponds.
After 9 years of planting them, I have yet to hear of one client unhappy with their invasiveness. They don�t appear on their own in ponds, their seeds are scattered by flowing water, not by wind.
Like all aquatic plants, they like colonies. Plant them in a group and if they don�t have a good amount of organic soil to expand in, they wont grow that fast.
As far as their importance for dragonflies and their larvae�s, they are a key plant to have. They are emergent, we planted them successfully up to 2 feet deep in water. They are also drought resistant if water drops a bit. And their flowers are beautiful.
I personally think that to be called a weed does not give it the respect it should have as a perfect pond plant! Match it with colonies of Arrowheads (Saggitaria latifolia), sure beats cattails!!! They keep shores cooler also.
