All aquatic vegetation supplies some type of habitat. Yes smaller fish will hide within thick stands of primrose and yes bass and larger bluegill will hide out on perimeter of primrose. However it does make fishing difficult because it tends to make thick mats which can easily foul hooks.

Grass carp and/or tilapia generally have little effect on primrose because it is a shoreline emergent plant. If grass carp have nothing else to eat they will nibble on primrose but don't expect miracles.

Primrose also dislikes fluctuating water levels. If primrose gets flooded it will generally die on it's own. If water levels drop slowly then primrose can get established and be difficult to manage.

Your best bet is to use glyphosate a surfactant or imazypyr and a surfactant. However don't use together as you won't get results you are after. I speak from personal experience. I prefer a different surfactant than Mr. Davidson but Cide Kick should work. I would use a surfactant that is labeled for aquatic purposes.

Fisheries Biologist, Texoma Hatchery.
www.texomahatchery.com