I believe it is by appointment when you purchase tickets.
It is open but you have to buy your tickets online in advance and then be there by your assigned time
I am only saying because thus far we have used it many times, and I purchased it only a month ago, but I suggest becoming a member. Its worth it 100%. You can go to all three, whenever they are open, as many times as you want. We go to the Botanical Gardens just to go far a walk. Learning all the different plants and trees. It's amazing.
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