I do not think it is spider mites ...or do you in wet rainy days on the butterfly bush leaves?

What should I do? Rained here the most in 20 years in June...this year

I have them all planted on elevated area, mulch is pulled 8 inches away from base of each
buzz butterfly bush..

Any idea on what to do will they die or what is causing the yellowing on half of each butterfly bush?
The pink butterfly bush has some yellowing on it today as all of them do but the blue skinny one has dropped leaves and has some brown at base..it gets sun there when not raining..
See the yellow leaves in one picture also..

sheri