This style of photography is referred to by several different names, camera painting and impressionism, to name a couple. I prefer impressionism because that’s what Michael Frye calls it and he grandfathered the technique.
I came upon a meadow above Jackson Reservoir just north of Truckee, the meadow was full with hot pink fireweed. The fiery plumes looked as though they were launched by green fireworks. I got up close and as I took the shot I quickly, in short strokes, moved my camera up and down. The result a lovely blur of color.