"Dark Shadows"

I saw this bizarre scene at Metro Beach Metropark. The green was duckweed, which had total covered the swampy areas. The late afternoon sun created dramatic shadows. I started this painting a couple months ago, but the shadow area just didn't look right. So I let it sit for a while while I figured out how to finish it. I finally decided to mix up a blue color for she shadow, then spread it on the canvas with a towel. Eureka! I think my solution sorta works.