Sunmark Wildflower mixtures are formulated on the basis of climatic conditions (rainfall, temperature range, humidity) and elevation. All mixtures contain 16 to 22 species. Annuals have been included to establish cover quickly and to give color the first year; some may produce new plants the following year (the biennials may also reseed). Perennial plants live for more than two years and flower from the second year onward. All species require full or partial sun, with the exception of those in the Shade Mixture. Sunmark mixtures are blended to give the widest possible range of colors and periods of bloom. Mixtures may vary occasionally from the indicated listing based on availability of individual species.