Bump

I have clump of mondo grass that only grows about 8" and the roots form a thick mat. That would help control erosion. It spreads pretty quickly, too.

Juniper really needs sun. Is this area sunny? The cheapest solution is a ground cover that is readily available for dividing, like daylilies, pachysandra, vinca, etc. The first thing I would do is cover the weeds (don't pull - you want their roots to hold the soil as long as possible) with layers of newspaper, wet and cover with (free) woodchips. Then start planting through it. With the mulch and paper in place you can take your time. Take care to see that your new plantings are absorbing water. If in doubt, create "wells" around the plants with rocks and packed soil to hold it. Provide more information about your conditions to get the best plant recommendations. In my state, our environmental conservation agency is a good source of advice on best plants for situations like yours and also sells starter plants very cheaply once a year. I recommend contacting them as well as your local (county, usually) cooperative extension office. Good government at its best!