My sister, Becky, has a creative knack with outdoor arrangements on her country property. Check out this vintage bicycle she just painted a warm yellow and added to her chicken coop display. It stands out in stark contrast to the lush greenery behind it and is balanced with other repetitions of yellow.
Contrast, of course, is a main principle in any art or quilting composition. Without contrast, there is no design. Here are a few examples of strong contrast using yellow.
Whether you're gardening or quilting, consider adding a splash of cheer with some yellow stuff.