What nice mailpeople!
Slopes are so hard to work with- a street near my mom's house had yards like that and only a few bit the bullet and did terraces.
My sister bought new in Florida 30 years ago.. they planted easily 2x what number of plants it should have had.
I have the liriope in my own yard.
it is so easy to use.
Your building could easily break that liriope up with patches of Autumn Joy or another sedum. Another (previously overused) tough plant.
Japanese barberry still seems popular with builders. How many owners are willing to keep that up, with the thorns?