> "retention walls", "planted slopes" == "landscaping"

They're just going to throw down a grass and wildflower seed mix, with a few trees here and there. Just like every other stretch of highway. There is nothing better nor cheaper. Grass retains the soil, trees retain the slope.

> The walls will be replaced with slopes planted with grass and wildflowers to make it more environmentally friendly and to retain the soil. Some trees will be replaced.

What do you suggest as a better or cheaper alternative?