The new nature play area at the Des Moines Botanical Garden opened in 2023. It's located on the far northern end of the garden. It's a nice addition, but there are definitely better nature play areas in the metro area and as a bonus, those don't require an admission fee.
We typically visit with an Iowa Adventure Pass, but I didn't book one for today because I thought our Reiman Gardens membership covered admission. Unfortunately, I didn't know that only two guests are allowed with a reciprocal membership, so we did have to pay an admission fee.