Achillea: Duizendblad Not only does yarrow tolerate heat and drought like a champion, but this easy-growing perennial is also a great cut flower and deer, rabbits, and most other pests won't touch it. Full sun and well-drained soil
Euphorbia polychroma - cushion spurge- Electric yellow bracts bloom on a low cushion in April and persist, but gently fade as the stems elongate to form a mound by midsummer. The leaves produce shades of red, orange, and purple in autumn.
Commonly called Basket of Gold, perennial alyssum makes a wonderful wall or rock garden plant. Every spring it develops masses of cheerful yellow flowers that look terrific tucked between rocks and boulders. - Flower Beds and Gardens
Avena grass, or blue oat grass, has yellow flower spikes in summer and silvery blue leaves. This interesting plant makes a fine structural accent and will thrive in a dry, sunny area. Learn more about this distinctive plant.