I had bought this wisteria plant on December 20th, 2015 & had planted it on the same day. The plant was watered weekly, leaving no stagnant water. After around 15-20 days the leaf-ends started to turn brown & black. It seemed like leaf rot to me. I prepared a solution of .75 tablespoon baking soda, 1 tablespoon mustard oil, 2 tablespoon of dish-washing liquid in 500 ml water & sprayed very lightly just once as it covered most of the leaves. Now the leaves look really sick & the issue seems to have spread more. I am from India and temperatures now range between 23-10 C. Please tell from the image what seems to be the problem from some of the pictures. The stem seems green though..
