In my Zone 8b yard, Willits, CA, this plant is competitive and persistent--not as bad as my Vinca minor, but worse than the Hypericum calycinum. It's been classed "Invasive" in Washington state, and shown to be a problem in NE Minnesota, SE New York state, and New Jersey--as well as other states. Here, it thrives in slightly acid soil that is wet in late winter-early spring, and hangs on, no watering, during summer drought. It is growing in nearly full shade. Its early spring blossoms are nice in bouquets.