..oh, I also considered ice plant too. Not sure if they would work well on this hill or not. But I like the fact that they bloom all summer. What I thought would look really cool is some type of blue colored plant coming down from the top into this dirst section in the middle. Have it look like a waterfall maybe. The only plants i've seen with a decent blue flower though is the Emerald Blue Creeping Phlox.....though they look more lavender in a lot of pictures I've seen.

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You must get at least some sun in this area because those roses on the left side are blooming like crazy. Groundcover roses will often tolerate some shade and will prevent erosion without taking over the universe. Pawnee Buttes sand cherry will spread about 6 feet, offer white spring flowers and red fall foliage. But it prefers drier areas, and I don't know how much rainfall you get.Groundcovers beautify garden while preventing weeds

Check out Lithodora.

Couple of thoughts:

For effective erosion control, you need an evergreen plant. Nearly every part of the country (except maybe the southwest) gets a reasonable amount of rain in winter and that's when most of the erosion happens. Or in early spring before things have leafed out.

I can't think of ANY groundcover that has a particularly long bloom period - a month at best in most cases (except maybe iceplant, Delosperma, but doesn't sound like enough sun for that to be happy.

And you want a groundcover that roots as it goes. That's where the erosion control comes into play also - you need a dense, spreading root system to hold the soil in place.

Lithodora is not a bad suggestion. Not an exceptionally long bloom time - finished in my area by late spring/early summer. Screaming blue flowers. But it is evergreen and each plant can spread to about 3-4'. The only drawback is it can look pretty ratty after winter and generally needs a good grooming/cutting back, which could prove tricky on that slope. And not all that effective at keeping weeds at bay. It's rather loosely knit in its growth habit and weeds come up easily in between the stems/runners.

My favorite ground cover for this situation is creeping raspberry, Rubus calycinoides. Has a very directional flow to its growth so will appear to flow down the slope. Evergreen, with a great foliage texture and bronze winter coloring. It layers upon itself making a thick mat so ideal for weed suppression. But flowering is sporadic, the occasional white strawberry-like flower followed by an edible gold berry. Not the slightest bit invasive, either.