Hi all! I just potted 2 dwarf Alberta Spruce (about 2 ft. tall) in large containers for my front lawn. They are both in full sun and protected from wind. One is potted in regular potting soil with a small mixture of manure/humus mixed in. The other one (since I ran out of the potting soil) is mostly garden soil and humus. The one in the garden soil is doing beautifully, but the one in potting soil has yellowing needles in a scattered pattern all around the tree. At first I thought it might have been underwatered but after a full day of rain yesterday, it looks even worse! Can anyone help me figure this out so I don't lose my cute little tree? Thanks!