I fixed the scale of the white flowers on the right, as well as the scale of the water texture. I also added a texture to the rocks.
Edit: For a bit of a technical detail here, if you look really closely, you can see a weird texture error in this image. Here is a zoomed in image,
If you look at the water, you can see that there is a texture that sort of looks like construction paper or something. This is due to not having enough samples using a specific sampling pattern referred to as sobol. Here is sort of what the pattern looks like:
It is honestly pretty hard to see, but once you see it you can't really not see it. The pattern goes away when you increase the samples for the integrator within mitsuba. I just need to remember to do that before I upload stuff here!
Edit again: I had to upload a better image, since I kept noticing artifacts from the low sample rate.