Hi John

Members with more expertise than me will chime in soon; but I would put a wooden stake at the end of each batch of primrose. This will give you a visual marker for how much it expands.

Also put a stake out in the water where it stops growing. I've watched it take over shoreline on ponds in the past so bad that you couldn't fish from the bank. I would think that not having any st
ructure/vegetation primrose might be good for the small fish.

But it will impede your predators from getting to their prey. Just be ready to treat it with chemicals if needed.

Say,I was at the Coonhunters Club shooting sporting clays sunday.We go once a month. Great area of In.