Especially pretty is the little bluestem. The bluestem will make a nice filler for a "meadow" on a slope. I see it growing in the most inhospitable spots on steep rocky slopes and its gorgeous when abused like that, straight up and distinctive like "starched" grass. I would DEFINITELY plant some there. It is so pretty in the fall with the way it catches the light and turns colors.

Some very easy, long blooming wildflowers to plant are horsemint, purple winecups, rudbeckia (black eyed susan's) and Oenothera speciosa (Mexican evening primrose). These will re-seed abundantly. The primrose is rugged but I have never started it from seed. Its nearly impossible to get rid of once you have it and will form a sprawling, wide mat of pink. I saw it along the highway yesterday on a slope and it must have covered a 6ft by 6 ft area. Very pretty. Missouri primrose is another good choice. It puts out a long tap root, needs very little water and blooms all season with large yellow blooms and will naturalize well.

Another wildflower I love, because it blooms from early spring until well past first frost is Baileya multiradata (Desert Marigold) It is a very neat, very light blue, fuzzy foliaged plant with a huge bouquet of bright yellow flowers all season. One plant can get very wide with hundreds of blooms non stop. I have this naturalized in my yard and get more comments on it that any other plant and its so EASY! All it needs is perfect drainage and a steep slope sounds perfect. It puts out hundreds of seed and will naturalize all over the slope if its happy.

A succulent that I find will grow in extremely dry soil is Talinum calycinum (Flame Flower). It reseeds like rosemoss and has magenta colored flowers on very thin stems.

Thelosperma will naturalize abundantly. I had one plant two years ago and now they come up everywhere. Blooms all spring, summer and fall. Some are solid yellow and some have red centers in the flowers, which are small but abundant.

You can get these seeds from Plants of the Southwest for $3.00/pk. They have a large selection of wildflowers to choose from.

As time goes by, you can add to the plants but these are some "easy to germinate and grow" ones to start with. A slope like that allows for perfect drainage which means you can grow lots of dry loving plants that otherwise would fail. A trip outside of city limits is something you could try and look around for wildflowers and native grasses in your area. It can get addictive.