Wildflowers that are okay to pick

Wanted to pick some flowers that I've seen around (poppies, red campio etc) but wasn't sure where good spots would be where I can pick a few without taking it away for people enjoying them out walking if that makes sense? Obviously just a few to put in a vase. Do people think that this is okay? And if so where around probably the marshes are there an abundance where a few won't be missed