I loved nasturtiums in the San Francisco Bay Area as a student. They flourished in the cool, wet winters, and foggy dry summers. I've only seen them here in the last few years, grown for our cool climate periods in spring and fall. I've enjoyed them in baskets, and mixed in with vegetables. Normally, they've died back in summer, to reappear in fall, but these, perhaps buffered by morning and afternoon shade, and with a minimal amount of blasting sun, have flourished at the base of the Armenian cucumbers.
Maybe the light conditions have determined the success of the cucumbers, too. I just harvested the largest ones -- quite tasty.