Jo I have had two plants this year die that have done the same thing. I realized that the plants that I purchased at Lowes are in side by the door but still inside and cool. I did not even put them in the sun but just the brightness of being outdoors and the heat of summer the leaves I think suffer so much from the heat and much brighter light than they have been growing in makes the leaves collapse.
I started keeping the plants inside close to the windows for at least a week before I take them outside now when I purchase the plants. That way they get use to sunlight in a much cooler environment inside because of the air condition. Then I put them outside in total shade for another week or so before I introduce them to the real sunny world.
It is strange but even the plants at my local nursery do the same thing when I bring them home and introduce them to the sunny outdoors. They have their plants outside but they are bunched up in corners and do not get a lot of sun so there again putting them outside on my patio is just too much to fast.
