Someone made the brocho of “oseh ma'aseh braishis” on a rainbow. Is this a brocho levatoloh? What sources deal with this issue please? (I have posed the shaaloh to my Rav.)
The Maharsha (to Berachos 59a) explains that the end of the beracha on the rainbow וקיים במאמרו refers to the fact that the rainbow was created during the 6 days of creation (as listed in Avos 5:6). So perhaps you could make an argument that by saying עושה מעשה בראשית you are including such things as the rainbow?
http://revach.net/ask/article.php?id=547 It seems that the rainbow bracha is for a very specific thing (which, mind you, took place over 1600 years after maaseh vereishit) so it doesn't get covered by the other standard nature brachot.
Also, in the book Shaar HaAyin by Rabbi Eliyahu Ariel, in Chapter 12 footnote 1 he quotes Rabbi Chaim Kanievsky (sp?) that the blessing does not work even post facto and one would need to still recite the appropriate blessing.