Anise Hyssop

Sow seed on the surface in spring

Sow in spring and barely cover the seed, pressing it onto the soil surface rather than burying it. Expect germination in one to four weeks. A period of cold, moist stratification before sowing raises the strike rate, and plants sown this way often bloom their first year. Anise hyssop seed needs light to germinate, so seed buried at any depth simply sits there and rots.

Divide the clump every few years to keep it alive

Lift and split the rhizomatous clump in spring or fall, replanting the vigorous outer pieces 12 to 36 inches apart and discarding the woody center. Sterile hybrids like Blue Fortune will not come true from seed, so division or semi-ripe summer cuttings are the only way to keep them going. Anise hyssop is a short-lived perennial that spreads by rhizomes, so dividing renews the clump before the original crown gives out.

Deadhead through bloom, then stop and let it set seed

Cut spent flower spikes off as they fade through the first half of the bloom season to pull a second flush of flowers. Once bloom is winding down toward fall, stop deadheading and let the last spikes ripen into seed. Removing spent spikes denies the plant its seed set, so it pushes out more flowers instead. Letting the final spikes mature gives you self-sown replacements for a perennial that does not live long, plus seed for birds.

Clear last year's dead stalks as new growth emerges

Leave the dead stalks standing all winter. Cut them off in spring once new foliage starts pushing from the base of the plant. Cutting the stalks down after a hard frost strips the crown of its own winter cover and leaves the seed heads unavailable to birds. The emerging basal foliage is the signal that the plant survived and no longer needs them.

Watch for powdery mildew and leaf spot in humid weather

Check the foliage through humid stretches for powdery mildew, fungal leaf spots and rust. Manage it by spacing plants 12 to 36 inches apart and siting them where air moves freely rather than by spraying. If the crown is collapsing rather than the leaves spotting, the cause is wet soil, not a foliar disease. These are humidity diseases that take hold in still, crowded air. Anise hyssop has no significant insect pests, so the whole disease question is a siting and airflow question.

⚠ This plant is a magnet for bees, wasps, butterflies and hummingbirds and needs no insecticide. Do not spray insecticide on it, especially in bloom.

Cut leaves for drying just past full bloom

Leaves are usable any time through the season, but for tea or drying take them when the flowers are just past full bloom. Flower spikes can be cut at the same time for fresh or dried arrangements, and both leaves and flowers are edible. Essential oil content in the foliage peaks just past full bloom, which is when the anise flavor is strongest.