Watercolor is something of a mystery. The way the paint and water interact is not always predictable. That is part of both the beauty and the frustration of painting with watercolor. You have to be open to the “happy accidents”. I don’t know who coined that phrase, but it is really appropriate.
Before I moved to Arizona I thought the desert was rather monotone and that painting a desert landscape would not lend itself to using a wide variety of colors. But, now I realize there is no limit to the variety of colors in the landscapes I see.