We planted vinca (the annual) here in SE MI this year and so far it is not looking good. It was reported to be very drought dolerant etc.etc.. We have had lots of rain here in Detroit over the past 2 weeks and I fertilized these flowers with a Miracle-Gro sprayer this past week. Well, some are wilting and some leaves have turned yellow. I sprayed them down with water to wash off any Miracle-Gro in case this was a problem. Any ideas? They get plenty of water due to the rain and we have a dripline matrix in this bed. (no, we didn't run the drip with all this rain) We grew Begonias successfully in this area last year.