I was going to book the NY Botanical Gardens. I didn't look at the Brooklyn site because I believe it's more expensive than the NY. I've heard the food is very good at both locations. Back in the day I used to watch Martha Stewart and she would always feature weddings there. The only problem I've heard about the Brooklyn site is that you will lose some guests during the cocktail hour walking around the gardens. It's kinda hard to find information about both places which I think is great because it makes them unique. I gave a lot of thought about a garden wedding but in the end for me the dance floor at the NY Bot Gardens didn't seem large enough even though they said the room could hold up to 300 people. I don't know if you would be interested in the NY Bot Gar but I do have some pics maybe you'd like to see....I think I originally found them on here.
For date I would probably say late May but July would also be nice. We were going to have ours in July because the price was a little less but then I started to hear that the flowers don't look as well in July. But, my response was that there is no way the flowers at both places could ever look bad in any month. They are beautiful places no matter what.
