Since I, and some others of you, model the anthracite area (NEPA) We NEED birches as background, middleground and foreground models. I did come up with a way of modeling the middle ground trees (photo 3) a few years ago but, until now, hadn't come up with a way to make foreground models. The butterfly bush flowers looked like they had possibilities. (The distant trees are painted on the back drop.)
You'll notice in photo 1 (taken in Lansdale, PA) and photo 2 (my back yard) that unlike oaks, maples and other deciduous trees birches are thin bottom to top. This is a plus since it's not necessary to add thickness as you would, say, to "super trees". I simply cleaned off the flowers, painted the trunk and branches white, added Polyfiber very sparingly and, after a dose of (cheap) hairspray, added some ground foam foliage. I painted the black markings on the trunks afterward.
Enjoy, Wayne Sittner