I installed a new landscape about 4-5 months ago. So everything is new and hasn't rooted well. The soil holds moisture well and once I started digging holes noticed a decent amount of clay. I took the soil from the holes and mixed with some potting soil. I've started losing some plants and upon further inspection notice that the soil around the plants was soft and when stepped on would bring water to the top. I'm guessing that when digging the holes I created a "bowl" and it is holding the moisture. Yesterday I went around and tried to pack the soil and add some more potting soil to dry it out. Is there anything I can do to help the drainage and fix the problem? I'm trying to keep from losing anymore and maybe recover some weaker plants.