Has it been really really windy? You say it's been raining a lot but that looks like my plants when it need water. Otherwise it's a possibility of root problems. Have you tried using hydroguard or I also like garden friendly fungacide which is the same type of bacteria as hydroguard but in a much higher concentration. You add either to water and french the roots. Also I've had great success with neem oil root drench. 2mg per gallon.