lilac bush questions

I have a lilac bush question:  I have two lilac bushes at the bottom of our lot, eastern kansas...they were here when we bought.  I read they need well drained soil but are currently sitting in very moist soil.  I cut some the other day and put them in water. they wilted right away:(  what happened?? it was right after an allday allnight rain???????

picture is right after I cut them looking good, but next day I noticed all wilted:(