I found out about them when I started reading more about aquascaping and different aquarium plants. I do not remember how did I find them, but I am a member I think 3 years already and I have learned so much from them. Multiple workshops, lectures, presentations, knowledge exchange with other members of Aquatic Plants Society Chicago gave me a lot of experience.
They are always willing to help when you need advice and share with you their trimmings on the meetings. Later on you can pay them off by bringing your trimmings, therefore helping out a new members get plants which normally they wouldn't be able to get easily. Thru them I found out about aquascaping competitions and had pleasure to attend to one of them (Fluval nano cube aquascape in 2017).
I think more people should know about them. As it is right now it is the biggest this kind of aquarium plants organization in US. Here I am sharing link to their website If someone would like to know more about them.