We have had a lot of rain in the past week 1.25" and then 2 days later at least the same amount. My tall plants are suffering a bit. Lots of broken, soggy blooms, and a few broken laterals. I do a really good job of staking and tying them up as they grow, but my stakes are only so tall, after that they are on their own. On some of the plants, when I cut to bring in flowers for vases, I cut them 18-24" just to take some of the height off the plant.
While the dahlias are handling it fairly well - my tomatoes took a tumble the night before last. (they get really tall too - due to my shadyish yard) Three of the stakes broke and two massive plants that were sort of staked/tied together, completely collapsed. I managed to get them back vertical again, and with amazingly not much breakage, but I am hoping the rain lets up a bit.