Hey, I'm not an environment artist, but I do make hair cards which follow a very similar pipeline. You're right that the reason you would want to follow the shape of the leaves is to avoid too many overlapping transparent pixels but as engines have advanced, the amount that this improves optimisation is negligible and so…
Foliage cards I painted myself in Photoshop to run through Maya for the big tree! The leaves and flowers are based off of the Dipteryx oleifera tree species from South America. I figured since the setting is a greenhouse and the other plants in the scene will likely be tropical I should keep this consistent with the design…