Maybe they weren't acclimated before you planted them? Were they in "mostly sun" where you purchased them? When I buy something I usually try to wait a few days before I plant it. I try to get it used to it''s new environment (light conditions) before I plant it and this usually works. Mine love the rain!

Tropcialfreak

I did, actually. They were in place a whole week in their nursery pots. I've not had mandevilla before, and didn't know if they could take all that water! Tropicalfreak, are yours planted in pots or ground? Does it make a difference?

- Robin

Forgot to add; the established ivy in the pots has frizzled, too! That's why I thought it might be a water problem.