I like to dabble with pond plants and have found that the most reliable way to find plants that will thrive in your pond is to look at the ponds near your area. If a certain type of plant grows out of control in a local BOW...chances are that it will in your BOW, likewise for the opposite. If you do not see any native arrowhead in older established public waters (or otherwise), chances are it will not do well in your waters.
There are exceptions, but it can be costly and take time to find out what those are with trail and error by buying plants online and giving them the season to prove themselves.
The arrowhead in my pond is a blessing. They are tropical looking, bloom nicely, and don't grow in water deeper than a foot or so. They are a little unsightly once they die back in the fall, but the dead matter can be cut and removed from the pond if you catch it before it turns to mushy matter and start to float about and sink.
I have a Water Hyacinth experiment going this year that may be of interest to you if you are looking to put some work into it to remove plant matter once it pulls the nutrients out of the water.
I can't say much about their effectiveness in my region just yet, let alone further north.
Here;s the thread...
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=508366&page=1
