Bamboo Brushes

Here's a nice set of 13 bamboo foliage brushes. I like all the different leaves on here.
> Bamboo Brushes

Foliage Textures and stock

38 free stock images and textures of ivy, plants, grass, leaves, and other foliage. These were intended for use for 3D textures. But there's no reason you can't use them for other things like backgrounds, brushes, and photoshop textures.

> Foliage Textures

Floral Brushes

Some high res floral brushes to tickle your fancy. Created by Jaaaiiro.
High Res Floral Brushes