4 years ago i planted a Weeping Willow that my grandfather got me as a house warming gift because its my favorite tree. last fall i trimed up the bottom of the tree and cut about 8 branches off of it completely (at the time i thought you were supposed to trim in fall i now no its in spring) but now this year the top branches started to bud out but they never developed into leaves the bottom and middle branches are full of leaves and mostly pretty healthy looking one branch however the leaves are turning yellow did i kill the tree by trimming it to close to winter? is there anything i can do to hopefully save this tree or is it a lost cause? or am i just being to anxious and i should just leave it be?