There are 3 white trees in the whole grazelands, 2 infront of that castle (i like those, makes sense to have beautiful trees there) and one in nature (- this one looks a bit off i agree, but they actually do stand out like that in real life too when surrounded by trees that are mostly green, they're flowering, and flowers stands out - it's their purpose in nature after all)
The pink is a litte bit more common, but there's only 10 of them in the whole area (i just checked the .esp to be sure).
If you mean the dark red ones they're not unique and acts as pure replacers (42 of those in the area).
While i do think you're overreacting a bit i'll make a patch with less colorful leaves for the red, pink and white trees.