Both the Spring and the Fall Plant Meet plant swaps are held at Mercer Arboretum in Humble, Texas just outside Spring and Houston.
22306 Aldine Westfield Rd
Humble, TX 77338
(View Google Map Here)
If coming from the south, southwest or west, you will take I-45 or the Hardy Toll Road, going north. Take the exit at FM 1960, and turn right (or East) on F.M. 1960. In roughly 1.2 miles turn left (or north) on Aldine Westfield. Shortly you’ll turn left into the Park entrance which will be at a light, directly across the street from Mercer Arboretum Botanical Gardens.
Once in the park, follow the road around. The Plant Meet is in pavilion on the right side of the road. There is a very nice playground just across the road. (J on the map below)