I am having mine outside in the courtyard at the Old Governor's Mansion. I know that you can do it outside at White Oak Plantation and there is also the 4th floor terrace at the Shaw Center. Hope this helps!
-magnolia mound plantation (owned by BREC on Nicholson) -white oak plantation (owned by john folse) -mt hope plantation (owned by lake house reception center, this is where I got married- LOVE it) -lake house reception center (not sure the outdoor situation...) -houmas house (20 minutes outside of baton rouge, but worth the drive- absolutely beautiful!!) -the gatehouse (for smaller weddings) -river terrace at the shaw center downtown BR -old governor's mansion ---hope this helps!
fyi- a few of the best florists in BR: -lance hayes (old hammond hwy) -the cut flower (jefferson hwy) -bloom (government)