Anne,
Cardamine nuttallii seems to be the accepted name now. It is a woodland plant, growing in humusy soil under hardwoods or a mixture of hardwoods and conifers. The go dormant in the summer so they probably don't need much supplemental water. This is quite a variable species, with a range of flower color, basal leaf dissection, leaf mottling, plant height, etc. - there may be more than one species involved but no one has figured it out. It does spread by rhizomes but at least in the wild it is not terribly aggressive. It is a toothwort (i.e. "Dentaria") rather than a bittercress so it certainly doesn't have the invasiveness of the bittercresses. So I'd suspect that it wouldn't be too invasive for you but you should still keep an eye on it and be prepared to remove it if it spreads more than you would like.
There is an entry for Cardamine nuttallii in the book, "Encyclopedia of Northwest Native Plants for Gardens and Landscapes" By Kathleen A. Robson. You can view the entry via Google Books, it is on page 141.
Ed
