Zone?

Keep in mind that a lot of the qualities that make weeds a nuisance make them great for erosion control...plants that send out roots or stems in all directions can be "weedy" but the roots hold down the soil. (In Europe poison ivy has been planted for erosion control) If the slope is too steep the mulch could fall down this hill.

In theory, native grasses and especially American Beach Grass are the best erosion control.

Juniper is a decent choice. I kind of like spreading, suckering plants like Virginia Rose and Beach Plum, however. You can plant fewer, and hey will spread.

Ideally, you could put down an erosion control/barrier that would stay in place for a year or so while your plantings take hold and start to spread, but then the barrier would break down. I'm imagining something like large rolls of burlap that could be held down with ground staples with holes cut in spots to plant through. I know there are water permeable weed barriers, but I don't know how long they stay around. I would encourage some spreading vines or ground covers, preferably native, so they would be more likely to thrive with minimal care.

Martha

dont worry i have been a same problem, you can use geotextile to retaining soil keep strength

Here is a link that might be useful: geotextile