There is an area in my yard where grass will not grow. It is shaded, near a patch of woods, and on a slight slope. It seems like we replant grass every year, and it will not get established. Any suggestions?

Yes. Stop throwing money away on grass! The very first things that should be considered when siting any plant are its cultural requirements, or “location, location, location.” Many people don’t think about the lawn as a mass of plants, all requiring a special situation in order to thrive. So that said, go at your search backwards: “It is shaded, near a patch of woods, and on a slight slope.” What would work there? The combination of the slope and the tree roots likely also makes the area dry. Under those conditions, you may want to try Epimediums or Geranium macrorrhizum (bigroot geranium). If it’s not real dry, there’s a whole world of shade plants to play with.