To speed up the process without investing big bucks I would be looking for areas in the pond that have growth of the weeds you want. From there fence them off the fish and wildlife can't get to them. If you don't have any zones that have weeds you want.... buy what you want and fence them to protect and allow them to get established.
1.5acre LMB, YP, BG, RES, GSH, Seasonal Tilapia I subscribe to Pond Boss Magazine