Native wildflower seedings are great for slopes that are difficult to mow and/or impossible to plant. They are one of the best places to sow a wildflower mix as many of these natives are drought tolerant and thrive in shallow soils and harsh environments.
During my years answering retail nursery questions, one of the most frequently asked and difficult to answer questions was, "what can I plant on my bank"? I have learned that unless you want a monoculture of juniper another non native groundcover, the answer is a diverse planting of native wildflowers & grasses.
Planting non native groundcovers on a slope essentially creates an ecological desert as native insects and fauna, which are the basis of the natural food web, can't exist.
Consulting and design fees: $45 for first hour and $30 for each additional hour.