2nd Year Maturity. Open Pollinated. Perennial. Showstar Mix Astilbe flower seeds grow an ideal and unique substitute to more traditional seasonal blooms. Showstar Mix Astilbe is an easy flower to grow from seed and matures into feathery and herbaceous 12-18" tall perennials known to thrive in cool, wet summers. Showstar Mix Astilbe provides vast and hardy ground cover, a perfect grow for mass borders, open fields, and commercial and business properties. Astilbe is one of the most widely cultivated blooms of the last century and promises to add a touch of elegance to any planter, basket, or living room. 100 seeds.