Asked July 21, 2021, 9:04 PM EDT
Hennepin County Minnesota
Absolutely wait until it cools off the plant. Fall might be an option if we get regular rain again, but waiting until spring will probably be necessary for the best results. Watering restrictions will also impact what is best.
Over time the area will gradually flatten because the roots will rot and they will no longer hold the soil on what appears to be a slight slope. I recommend a smaller tree that will provide dappled shade to help your lawn survive hot summers. Or, the garden at the end of your lot could be expanded with another lobe and look very nice. The plant selection could be repeated. Grass is also an option. The mulch is a bonus, it will suppress weeds and improve the soil until it is cool enough to start adding new plants.