Anise hyssop, Agastache foeniculum, is a short-lived herbaceous perennial with blue flowers and fragrant foliage that can be used as an ornamental or in the herb garden. Native to prairies, dry upland forested areas, plains and fields in the upper Midwest and Great Plains into Canada (from northern Colorado to Wisconsin and in Canada from Ontario west to British Columbia), this plant in the mint family (Lamiaceae) is hardy in zones 3 to 8.
Other common names include blue giant hyssop, fragrant giant hyssop and lavender giant hyssop. Despite the common name, it is not closely related to hyssop (Hyssopus spp.), a European plant traditionally used as a healing herb, or anise, Pimpinella anisum, a completely different plant in the carrot family (Apiaceae).
The upright, clump-forming plants generally grow 2-4 feet tall and about 1-3 feet wide from a small tap root with spreading rhizomes. They have opposite leaves on the square stems (characteristic of the mint plant family). The ovate to broad-lanceolate, dull green leaves up to four inches long have toothed margins and a whitish tint to the underside. The foliage remains nice looking throughout the season and sometimes has a purplish cast on the new growth.
The aromatic leaves have a licorice-like (anise) scent and are used in herbal teas, to flavor jellies or eaten fresh in small quantities, such as in a salad with other greens. The dried leaves can be used in potpourri. The plant was used medicinally by Native Americans. The best time to harvest foliage to dry is when the flowers are just past full bloom, as the oil content in the leaves is the highest at that time, but they can be used at any time.
By midsummer erect terminal cylindrical flower spikes begin to form and continue blooming through fall. The tiny flowers occur in dense, showy verticillasters, or false whorls tightly packed together, that are 3 to 6 inches long. Each tubular flower has two lips like all plants in the mint family, with the lower lip having two small lateral lobes and a larger central lobe and four stamens ending in blue-purple anthers and a cleft style that extend from the flower throat.
Flower color varies from white to pale blue and lavender through blue-purple, with the color more intense at the tip. The unscented flowers are very attractive to bees – particularly bumblebees, butterflies, beetles and other insects that feed on the nectar or pollen, as well as hummingbirds. Pollinated flowers produce smooth, oval-shaped fruit or seeds that are technically nutlets. Deadhead spent flowers to promote additional bloom. The flower spikes can be cut to use in fresh arrangements or to dry, and the flowers are edible. Plants self-sow readily but undesired seedlings are easy to pull. Goldfinches and other birds may feed on the seeds.
Anise hyssop works well in the middle or back of perennial borders, native or wildflower gardens, cottage gardens, and herb gardens, as well as in meadows and prairies. It can be grown in masses, drifts, or in small clumps. It combines well with other natives such as the biennial brown-eyed Susan (Rudbeckia triloba), goldenrods such as Solidago rugosa ‘Fireworks’, purple coneflower (Echinacea purpurea), bee balm (Monarda spp.), false sunflower (Heliopsis helianthoides) and native grasses. In perennial gardens it mixes well with globe thistle (Echinops ritro), Japanese anemones, Russian sage (Perovskia atriplicifolia), and plants with purple foliage, such as Euphorbia dulcis ‘Chameleon’ or purple-leaved heucheras.
It can also be grown in containers, alone or in combination with other plants. In mixed beds combine it with Verbena bonariensis and various annuals and perennials. The chartreuse foliage of the cultivar ‘Golden Jubilee’ offers good foliar color contrast with other green- or purple-leaved plants.
Grow anise hyssop in full sun to partial shade. It tolerates a wide range of soils as long as there is good drainage. This plant has no significant pest problems but may develop root rot in wet soils or powdery mildew and leaf spots in humid climates. It tolerates drought once established but will also do well in moist soils as long as it has good drainage. It is not favored by deer but rabbits will eat this plant. It is easy to grow and rarely needs staking.
Anise hyssop is easily started from seed and often blooms the first year but also can be propagated in spring or fall by division of plants that spread by rhizomes. Seeds need light to germinate, so barely cover the seeds. They should germinate in 1-4 weeks; cold, moist stratification improves germination.
Self-sown seedlings can be easily transplanted when small; although they will wilt quickly when moved, the plants will recover in a few days. To collect seed, allow the flower spikes to dry on the plants and bag the spikes to capture ripening seed or remove from the plants to collect seeds. Sterile hybrids are propagated by semi-ripe cuttings taken in summer.
There are a number of cultivars of anise hyssop and a few hybrids with Korean hyssop (A. rugosa, Zones 5–9), which has deep violet–blue flowers and glossy green foliage on plants up to 2 feet tall and 15 inches wide. [There are also many other Agastache species and showy hybrids with pink, orange or red flowers, but these do not have A. foeniculum as a parent.]
Anise hyssop (Agastache foeniculum) is a lovely herbaceous perennial with fragrant foliage and beautiful blooms Both the leaves and flowers can be used fresh or dried in teas, potpourris, desserts, salads and more But to get the best quality and highest yields from your plants, it’s important to know the proper harvesting techniques for this versatile herb.
In this comprehensive guide, we will cover everything you need to know about successfully harvesting the leaves, flowers, seeds, and oils from anise hyssop.
When to Harvest Different Parts of Anise Hyssop
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Leaves – Anise hyssop leaves can be harvested anytime once the plant is established. Pinch off fresh leaves as needed for cooking. For sustainable harvesting do not take more than one-third of the existing leaves at one time to avoid stressing the plant.
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Flowers – Wait to cut anise hyssop flowers until they are fully open and vibrantly colored. Snip off individual stalks when at least half of the blooms on that stalk have opened up.
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Seeds – Allow the flowers to fade completely after bloom time ends. Seeds are mature when the dried flower heads turn brown and get brittle, releasing the seeds easily when crushed.
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Essential oils – For the highest essential oil content, harvest anise hyssop leaves and flowers just after the peak of blooming while the plants are most robust.
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Drying – Cut anise hyssop stems for drying when about half of the flowers per stalk are fully open. This ensures good color and flavor
How Often to Harvest Different Parts
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Leaves – Pinch off fresh leaf tips no more than once per week to maintain plant health. New growth will continually provide more leaves for harvests.
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Flowers – Deadheading spent blooms encourages reblooming. You can get a second flush of flowers by cutting back entire flower spikes after the initial bloom.
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Seeds – Seeds can be harvested just once at the end of the season when fully dry. Gently crush ripened seed heads and collect the released seeds.
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Essential oils – Anise hyssop leaves and flowers can be harvested up to 2-3 times per season for distillation if done carefully and not overharvested.
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Drying – Only harvest stems for drying one time per season. Remove any dead leaves from stems before drying to prevent molding.
How to Harvest Anise Hyssop Leaves
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Use clean, sterilized pruning shears or scissors to prevent spreading diseases.
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Select healthy, vibrant green leaves from established plants, ideally at least 2 feet tall.
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Snip off individual outer leaves near the stems, leaving at least one third of leaves still on the plant.
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Rinse and pat leaves dry before use. Store unwashed leaves in the fridge for 2-3 days max.
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Leaves can also be frozen, dried, or preserved in vinegar or oil. Freeze leaves in a single layer first before storage.
How to Harvest Anise Hyssop Flowers
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Use clean bypass pruners or floral scissors. Sterilize tools between plants.
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Snip off flower stalks when at least half of the individual blooms per stalk are fully open.
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For air drying, cut stems 6-10 inches long and bundle 3-4 together. Remove leaves from stems.
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Hang bundles upside down in a warm, dry, dark place until completely dried. Store in glass jars or tins.
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For distilling essential oils, process fresh flowers and leaves immediately after harvest.
How to Harvest Anise Hyssop Seeds
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Allow flowers to dry out completely once summer blooming finishes.
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Monitor dried flower heads daily and wait for them to turn brown and get brittle/crispy.
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Clip off entire dry flower spikes. Place in paper bags, then crush to separate the seeds.
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Spread seeds on a screen to dry further 1-2 weeks. Discard any moldy seeds.
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Store thoroughly dry seeds in labeled, dated glass jars in a cool, dark place.
Which Parts of Anise Hyssop are Used?
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Leaves – Used fresh or dried in teas, cocktails, jellies, fruit salads, marinades. Provides flavor and aroma.
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Flowers – Used dried in teas, potpourri, sachets. Can also be used fresh in salads or as a garnish.
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Seeds – Dried seeds used as a seasoning, similar to regular anise seeds. Often made into essential oils.
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Stems – The stems are not used. After harvesting leaves/flowers, the woody stems are discarded.
Proper harvesting technique, timing and care is key to getting the highest quality and maximum yields from anise hyssop. Follow these guidelines for the ideal harvest of leaves, flowers, seeds and oils. With some basic care, a single anise hyssop plant can provide abundant resources year after year.
Anise hyssop compaion planting
- Companion planting: Anise hyssop attracts butterflies, hummingbirds, honeybees, and other pollinators. It’s a good source of nectar in late summer and early fall. It repels cabbage moths. Plant anise hyssop with chamomile and horehound.
Recommended Anise Hyssop Cultivars
- ‘Alabaster’ – has creamy-white flowers on three foot high plants that have lighter green foliage and are not quite as bushy as the species.
- ‘Black Adder’ – is a hybrid with dark buds and red-violet flowers, but is less vigorous than the species.
- ‘Blue Blazes’ – a tall hybrid of A. foeniculum and Agastache ‘Desert Sunrise’ introduced by High Country Gardens that has pinkish calyxes and glowing lavender purple blooms. Hardy to zone 5.
- ‘Blue Fortune’ – a sterile hybrid of A. foeniculum and A. rugosa bred at Arboretum Trompenburg in Rotterdam, Netherlands. It has extremely thick spikes of powder blue flowers and large, deep green leaves. Plants grow to about 3 feet tall and 18 inches wide. Peak bloom is in midsummer and flowers last a very long time because it sets no seeds. It received the Royal Horticulture Society’s Award of Garden Merit in 2003.
- ‘Golden Jubilee’ – an All American Selection Winner (2003) with golden-chartreuse to lime-green foliage that is especially bright yellow in spring and normal lavender-blue flowers. Self-seedlings are mixed with some golden ones.
- ‘Purple Haze’ – a hybrid with narrow flower spikes that are of less interest to large native bees but still attracts many smaller pollinators
- ‘Red Fortune’ – a hybrid with pink flowers that are not nearly as attractive to pollinators as the species.
- ‘Snow Spike’ (also known as ‘Album’) – with white flowers on three foot plants.
– Susan Mahr, University of Wisconsin—Madison Last Update: Bruce Spangenberg, UW—Madison Extension, 2025
Harvesting Anise Hyssop: When, how, and why.
FAQ
What part of anise hyssop do you use?
The aromatic leaves have a licorice-like (anise) scent and are used in herbal teas, to flavor jellies or eaten fresh in small quantities, such as in a salad with other greens. The dried leaves can be used in potpourri. The plant was used medicinally by Native Americans.
How to harvest and use hyssop?
To harvest hyssop for medicinal use, cut the stem just before the flowers begin to open. Hang the bunches upside down in a warm dark place. Dried leaves, green (not woody) stems and flowers may be chopped and stored for later use once dried.
How to harvest anise for tea?
Harvesting aniseed from the garden
In any case, it is easy to tell when anise seeds are ripe, because they will turn brown. To harvest anise seeds, cut off an entire umbel in the morning, when it is dewy, and dry it indoors. It is important to do this in the morning, so that the seeds do not fall off the umbel.
What part of hyssop do you use for tea?
Leaves can be used as a seasoning, dried for use in tea, used fresh in salads, or made into jellies. As leaves maintain their scent well when dried, anise hyssop can also be used in potpourri.