When I worked in China Valley in the early 90s, there was Pollia in the collection. I worried about it because it spreads well by rhizomes and seeds prolifically. Well, almost 20 years later we do pull the occasional seedling but it doesn't seem to be the invasive problem that I had thought it might be. And it's beautiful.
A member of the commelinaceae, it grow to about .5m with glossy green more or less oblanceolate leaves; it looks a bit like a little ginger. The flowers aren't spectacular in late summer to fall, but the berries are, and the colony itself can be a very useful landscape element. I notice Annie's Annuals is listing it this year. For such an easy plant to propagate it's fairly uncommon in the trade.