I planted Oenothera 'Shimmer' expecting it to melt away like a cheap popsicle in the desert, but unlike other Midwest/Great Basin evening primroses, this plant is still going strong after three years. Oenothera 'Shimmer' is a hybrid (possibly Oenothera fremontii x Calylophus) discovered by Lauren Springer and Scott Ogden in their Colorado garden. For us, Oenothera 'Shimmer' makes a low 6" tall x 2' wide tight clump of lax stems adorned with very narrow silver-green leaves. The clumps are topped with 3" brilliant yellow, nocturnally-fragrant flowers in late spring and sporadically throughout the summer. A well-drained sunny site is essential for best performance.