Pigeon Peas

I adore pigeon peas.  They are a very common side dish in West Indies food - rice and pigeon peas.  While we were in Codrington, the only village on the island of Barbuda, our local guide Goldilocks showed us a pigeon peas tree.  I had no idea they were grown on tress.

Actually I didn't know how they were grown.  In Kansas the only way I was able to get them was in cans. Since being in the Caribbean  I have purchased dried and done them in the pressure cooker twice with only moderate success.  I am going to need to start getting some tips from locals on how specifically to cook them.

My other question is where they are grown commercially.  I doubt it's in the Caribbean.  Perhaps Mexico? Does anyone know?
UPDATE - I looked it up.  Pigeon peas are native to Africa.  India grows most of the world's pigeon peas.