There are lots of manufacturers of scenery and plants. I'm currently using some I purchased from Fredericus Rex in Germany and Reality in Scale. Not all of them are 1/16th scale, but if you pick only the taller grasses and the larger plants it should be workable. Avoid the matt ground covers and things like that. Those are intended for the model railroad market and are much too small.
There are a few 1/12th (doll house scale) paper plants made by garage manufacturers that may work. Check out Etsy and e-Bay to purchase.
All the best,
Dan
All the best,
Dan