Stipa Seeds - Pony Tails98 105 days. Pony Tails stipa seeds grow one of the most versatile ornamental plants available. Stipa can just as easily be grown indoors as it can be out in the garden. Pony Tails seeds deliver 36" tall feathered grasses with a dense 24" spread, ideal for large planters or garden boxes. Stipa is native to the most hot and arid regions throughout North and South America. 100 seeds. Growing Pony Tails Stipa Garden Seeds Taxonomy: Nassella tenuissima