Yellow is the primary colour for Spring, it appears early and keeps going, from January still in the depths of Winter through to May when the sun is warmer.
Winter Aconites, Crocus, Narcissi, Daffodils, Tulips. Flowers often with bold deep yellow hues. It is often said that many women dislike yellow flowers, yet when pressed, most like or at least tolerate yellow blooms in the Spring.
Designing planting schemes yellow is useful to lift other colours, notably blue and purple. Given strong material colours such as red brick, yellow is useful as it challenges the dominance of the material colour to the eye.
It is certainly a colour people have opinions about, and used carefully, it can be very helpful in the landscape.