Ipomoea alba noctiflora syn. Calonyction aculeatum is a Morning Glory relative and may be blooming its heart out because of the cloudy days rather than in spite of them.
Morning Glories open during the day and Moon Flowers open in the evening and early morning, as well as on cloudy days.
Cold hardy only to zone 9, it won't survive the winter here in zone 7, but maybe some seeds will fall and keep this beauty coming back to climb all over everything in its path.
Look at the bud before it opens and those purple stems in this photo taken yesterday.
Have you tried Google for Gardeners yet?
Here's the link. Try it and let me know if you find what you are looking for. I have not.
I still find Dogpile.com to be the most efficient search engine, though I try every new one that comes along. And, Dogpile searches benefit our furry friends.