Okay, it is pretty, but it's horribly invasive. They'll take over your hillside - and NO, don't plant them just so they will cover up your hillside. Because they'll also take over the neighbor's hillside and all the hillsides that the wind can blow it's seeds to. So PLEASE don't ever plant this plant.
Check the following website to learn why this plant is so invasive and what damage it can do to our eco-system. They also give alternatives to plant. www.plantright.org