Beginner Gardening: mandevilla vine slowly turns yellow, 2 by fescue_fan

fescue_fan wrote:
Hi all..I\'m trying to grow a mandevilla vines. I bought the vines from a nursery and put it in the ground in July. From July till 3 weeks ago, it was under a canopy of a big tree. It has may 1 or 2 hours of sunlight each day but it was growing really well. I chopped the big tree 3 weeks ago so now the mandevilla is under direct sunlight much longer. Ever since then, I notice some of the leaves are slowly turning yellow. I watered the same amount till a week ago since the guy at the nursery said I could be overwatering. Any idea on what causing this problem? Thanks. Below is a pic of the vines and one of the yellow leaves.