I have a row of hostas along a rock border in a bed that has been covered with landscape fabric that I am removing. They sit under a row of spruce trees. My initial thought is to fill in the low spots with fresh soil and top with mulch. Is this the way to do it properly? Also, should I incorporate a fertilizer like milorganite? Thank you!

If it were me, I would dig up each hosta and remove any feeder roots from the spruce trees that have spread through the hosta's root system. I'm not sure about fertilizer this late in the year? You could add some mushroom compost to the hole before replanting the Hostas.

Pics would be helpful, is this a rock much, I have not seen people have much luck with plants under established Fir trees.