This is a project that I typically do with 1st graders. It is a perfect lesson to discuss texture with the plants. They are just clippings from the school garden, and as a bonus your room will smell nice. I have done these with both red clay and white. I don't really have a preference, I think both turn out nicely. I do not introduce glazes until the 2nd grade, so for kinder and first I use alternative painting methods for clay. This is just a blending of acrylic paints, sponged on and a pearl medium added to the paints. On the third picture down, I added paints a little heavier and dripped metallic watercolor into the impressions. I have the kids roll out their own clay, press their plants, add hanging holes with a straw and sometimes we add the stamps to the edges, depending on the class and time.