Posted by Jessie Jacobson on Jul 9th 2024

Agastache (Anise Hyssop)

Exploding in a sea of purple-blue blooms buzzing with delighted pollinators all season long, Agastache foeniculum (ah-GAH-sta-kee fin-ICK-yoo-lum), commonly known as anise hyssop, is a versatile Minnesota native plant well-suited for the home landscape. A member of the mint family, Lamiaceae, hyssop produces upright square stems and aromatic, anise-scented foliage, maturing to an incredibly tall and lush upright mound of foliage - up to 48” tall and 24-36” wide. Agastache spreads gently by rhizomes to fill any sunny garden space.

Blooming throughout the summer for weeks on end and swarming with pollinators, including hummingbirds, their tubular, two-lipped flowers reach up to a third of an inch long, with four lavender stamens topped with purple anthers, as well as purple calyxes that offer lasting color well into the early fall, even after blooms begin to fade. Plants will also benefit from regular deadheading to promote dense regrowth and the production of additional flower spikes.

Agastache thrives in full sun areas in moist, well-drained soils, is drought tolerant after establishing a deep tap root system, and is generally unbothered by deer or rabbit feeding because of their lovely anise-scented foliage. Avoid over-mulching anise hyssop and ensure sites are well-drained as plants are prone to root rot in consistently wet and poorly drained areas, especially when dormant.

Though a typically shorter-lived perennial, lasting for three to five years on average, plants are durable, fast growers and will readily re-seed to continue thriving in the garden. Plants can also be split easily in the spring or fall. Just be sure to water new transplants thoroughly. A phenomenal, low maintenance plant that is worth replanting from time to time, anise hyssop is exceptional in pollinator gardens, rain gardens, cottage gardens, natural landscapes, sunny borders, sensory gardens, and background plantings, especially when mass planted, and is great in floral arrangements as well.

Unfortunately, the closely related, visually similar, non-native Korean Hyssop, Agastache rugosa, is increasingly mislabeled as native Agastache foeniculum, posing a threat to native anise hyssop due to hybridization and seed source contamination, with plants seeding and spreading prolifically once planted. This problem has been of special concern here in Minnesota lately, and gardeners should ensure they have the correct species. Though we strive to only carry the true native as labeled here at Tonkadale. True native anise hyssop leaves should end in a sharp point, will be more slender than round in shape, have fine, sharply toothed margins, not more open, rounded toothing, will be dusty green in color on the undersides of leaves due to soft dense hairs, not sparsely hairy with coarse hair mostly concentrated along leaf margins along with circular markings or areoles, and will have a green flower base, not a purple base.

Happy planting!