I found a site that even says to be cautious in planting
S. striatum near wet areas (implying invasiveness) so it makes sense that that one would certainly be at home in the wet.
http://www.pnwplants.wsu.edu/P...
S. californicum is native to wet, coastal areas, so that makes sense too:
http://www.calfloranursery.com...
Hmmm, I've never thought of
S. montanum particularly as a wetland plant, but eFlora of North America does note it not just in grasslands but also in moist meadows and along streams. Interesting...