When we built the house 2-and-a-half years ago, this hill was covered with Japanese Knotweed, mugwort, Virginia Creeper, blackberries, and all sorts of other less-aggressive.

Our clay-and-rock soil is not prone to giant slides, only regular erosion, so we elected not to build a wall and just to plant. We could not clear the whole thing at once, nor did we think it wise to do so, so we cleared out areas for plants and protected them with rings of newspaper and mulch, and gradually as the plants grew in we pulled out more and more weeds. We have used some cardboard to suppress the worst of the mugwort, but it's shallow-rooted so repeated hand-weeding does a pretty good job eradicating it (eventually).

The knotweed is another story altogether, and we have been using cut-and-paint with Roundup to slowly knock it back. It's still there, though you can't see it in these pics because we cleared it all out before laying down a truckload of mulch.

It's too early for the grasses and perennials to be big yet. WIth the exception of one viburnum, all the plants are cultivars of natives. We have:

Little bluestem
Switchgrass
Purple coneflower
Black-eyed susans (rudbeckia fulgida)
Phlox subulata
Red chokeberry
Serviceberry
An Eastern Redbud
Columbine (which was given to me and must be moved; it is NOT happy on this dry bank in mostly sun)
Penstemon Digitalis "Husker Red", my new favorite plant
Grey Owl Juniper

The black-eyed susans and little bluestem are reproducing like mad. The redbud would probably prefer more moisture and more shade, but I think it will be ok in another year or two when its roots are fully developed. The serviceberry are happy enough because they are at the bottom, where it's a little less dry.

We have very little problem with erosion, thanks to a rainbarrel under our downspout and some careful placement of rocks. We would like it to fill in a little more, of course. I want to add some prairie dropseed, and give blue-eyed grass a try (though I hear it can be hard to start). And I want to add some white coneflowers. I'm waiting til the purple ones I have are big enough to divide so I can add some drifts instead of individual plants.

With the exception of the autumn pic of Little Bluestem, all are from this year. The first two are the knotweed across the street, and the mugwort on an unplanted area of the same bank, to show how bad it was.