Rose campion - yellow leaves

hi

my rose campion seems to be growing yellow leaves, i have been taking some off but so many! not sure whats wrong, watered too much? too little? no problems? still flowering

any advice welcome!

thanks

 

I'm not sure, but it looks in need of water, or maybe there's some root problem stopping it taking up the water.
If the compost is too dry try watering it, if the compost is wet maybe you could tip it out of the pot to inspect the roots. Then take it from there ...