Taking pot luck with native plants is likely to lead to a free for all for the worst seeding and spreading aquatic plants of all. Cat tails and smartweed come to mind
Its a fairly common wheeze for supposed pond contractors to offer whatever they can get cheap, plants with some rather iffy pond busting habits, odorata waterlily hybrids, yellow flag iris, aggressive lotus as very cheap, or free to help you out (with the prospect of charging a hefty price to control them later, or to build a new pond as the old pond choked down the road)
Be picky about introducing plants which you know have a desirable mix of ornamental, habitat improving, well behaved and easy to control characteristics
Regards, andy
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