I visited in mid summer about 12 years ago and left very impressed! I would recommend contacting them and ask for their recommendation. There may be certain plants that look better whichever season you choose. They strive to keep visitors interested year round -- helps pay their bills!

Have you looked at their website? I think they've made a list of what has been in bloom when. So if there are some particular things you'd like to see in bloom, you can see when historically they've bloomed.

You really cannot pick a wrong time to visit. Even dead of winter it is beautiful. But why don't you try going in the spring and then maybe, just maybe you can go again in the summer! I can assure you that you are going to want to visit again once you've seen it.

And plan to spend a long time at the Missouri Botanical Gardens. Four to six hours if you are up to it. There is a lot to take in.

As previously stated, anytime is a beautiful time to visit. We live 3 hours away @ Paducah, KY so we go up a couple times per year. The spring flowers are wonderful and of course the roses in summer and all the summer flowers. They have the indoor activities also so basically anytime is wonderful. My daughter likes the zoo and science center and wife likes shopping and of course we hit "wine country" West of town, make it a weekend event, you will have a wonderful time.

I visit the Missouri Botanical Gardens every year in mid-May.
Have went other times but this is IMO the prettiest season. My birthday is May 21 so I ask to go here every year as my birthday gift :) Just go you'll love it what ever season you may choose.
Have Fun,
Loriann