What a great idea to stop mowing the steep slope. Instead you can turn this area into a terraced planting using large boulders or landscape timbers or if you want a dirt cheap option use groundcover plants to mix with native plants to cover the area. Your local nursery will be the best source of plant material that will mimic the nearby woods as I do not know how much sun the area gets or the type of soil on the slope. You may want to add a pathway of log or stone steps that snakes down the hill to a bench or other garden focal point. Evergreen groundcover shrubs such as low growing junipers or cotoneaster can cover and shade the ground to crowd out the grassy weeds but you will need to use a mulch on top of the soil while you wait for the groundcover shrubs to spread out and grow. One more quick trick is to put a post and rail fence using rustic wood like you would see around an old corral at the top of the hill. This will visually separate the area from your yard so you can just let it go wild. Keep growing, Marianne Binetti