Outsidepride Agastache Mexicana Lavender Blue - 1000 Seeds Agastache Mexicana Lavender Blue is a perennial that grows best in USDA Zones: 7 - 10. This Giant Hyssop commonly used for cut flowers or dried arrangements also has aromatic foliage that attracts both hummingbirds and butterflies. This highly scented heirloom flower grows 26 - 32 inches tall and is heat and drought tolerant. Sow Agastache Lavender Blue at 3 seeds per plant and keep moist until germination. Our seeds are always Non-GMO and packaged for the current year.