I've been reading several comments with regards to the sometimes hostile policies towards photogs (specifically you wedding and portrait guys) on the part of Hermann Park. You know, there are alternatives and one such that I have run across in my short time in Houston is the Mercer Arboretum near IAH.
Mercer Arboretum & Botanic Gardens
Photo guidelines
Mercer Arboretum & Botanic Gardens
While they do have rules regarding photography, they do not require permits, all one has to do is sign in, follow the rules (mainly the "Stay Off The Grass" genre) and bam..you're in. They even have a Japanese Garden as well, granted not as elaborate as Hermann's, still nice. The weekends, are crawling with you portrait/wedding shooters. I go out there just to kill an afternoon once a week or so as it is very peaceful and relieves a lot of stress. While I am not a portrait/wedding shooter rather an ex-PJ (photojournalist) now shooting stock and editorial gigs, as a force of habit for 20+ years I still drag my rigs on the off chance something interesting pops up and got a few snaps at Mercer.
While Mercer may not have the 'bells & whistles' that Hermann offers, they are very photog friendly and offer a wonderful venue to shoot your portraits
to your heart's content.
Marty