120 days. Rocky Mountain penstemon is easy to grow from seed and ideal for gardens prone to heat and drought across North America. Rocky Mountain penstemon is native to arid pine and juniper forests from Wyoming down to New Mexico and tenacious performers in poor soil. Rocky Mountain penstemon seeds are a fragrant and simple grow indoors or out for either compact, urban, or traditional gardens. Rocky Mountain seeds promise neat 12-30" tall penstemons with rich, leafy greens and robust "snapdragon-like" stalks certain to excite any fresh cut arrangement, basket, or bouquet.