Agastache foeniculum, or anise hyssop, is a short-lived herbaceous perennial plant with blue flowers and fragrant leaves that can be used as a flower or in an herb garden. This plant comes from prairies, dry upland forests, plains, and fields in the upper Midwest and Great Plains into Canada (from northern Colorado to Wisconsin and from Ontario west to British Columbia in Canada). It is hardy in zones 3 to 8. It is in the mint family (Lamiaceae). 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 plant from Europe that has been used for thousands of years as a medicine; or anise, Pimpinella anisum, a completely different plant from the carrot family (Apiaceae). The plants grow in clumps and stand upright. They are usually 2 to 4 feet tall and 1 to 3 feet wide. They have a small tap root with spreading rhizomes. They have opposite leaves on the square stems (characteristic of the mint plant family). The leaves are dull green, ovate to broad-lanceolate, and up to four inches long. The edges are toothed, and the underside is whitish. The foliage remains nice looking throughout the season and sometimes has a purplish cast on the new growth. The fragrant leaves smell like anise and licorice. They are used to make herbal teas, flavor jellies, or eat them fresh in small amounts, like in a salad with other greens. The dried leaves can be used in potpourri. The plant was used medicinally by Native Americans. When the flowers are just about to go out of bloom is the best time to pick leaves to dry because they have the most oil. However, the leaves can be used at any time. By midsummer erect terminal cylindrical flower spikes begin to form and continue blooming through fall. There are many small flowers in 3 to 6 inch long false whorls that are closely packed together and very showy. Like all mint plants, this tubular flower has two lips. The lower lip has two small lateral lobes and a larger central lobe. It also has four stamens that end in blue-purple anthers and a cleft style that extends from the flower throat. The color of the flower ranges from white to pale blue, lavender to blue-purple, and the color is strongest at the very end. Bees, especially bumblebees, butterflies, beetles, and other bugs that eat the nectar or pollen, as well as hummingbirds, are very drawn to the flowers that don’t smell. Pollinated flowers produce smooth, oval-shaped fruit or seeds that are technically nutlets. Deadhead spent flowers to promote additional bloom. You can cut the flower spikes to use in fresh arrangements or to dry. You can also eat the flowers. Plants self-sow readily but undesired seedlings are easy to pull. Goldfinches and other birds may feed on the seeds. Anise hyssop grows well in meadows, prairies, cottage gardens, native or wildflower gardens, and herb gardens, especially in the middle or back of perennial borders. It can be grown in masses, drifts, or in small clumps. It grows well with other native plants like the brown-eyed Susan (Rudbeckia triloba), goldenrods (such as Solidago rugosa ‘Fireworks’), bee balm (Monarda spp.), and purple coneflower (Echinacea purpurea). ), false sunflower (Heliopsis helianthoides) and native grasses. It grows well in perennial gardens with Russian sage (Perovskia atriplicifolia), Japanese anemones, globe thistle (Echinops ritro), and plants that have purple leaves, like 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 leaves of the cultivar “Golden Jubilee” look good next to plants that have green or purple leaves. 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 doesn’t have many pest problems, but it can get root rot in wet soils or powdery mildew and leaf spots in humid places. For a while, it can handle drought, but it also does well in wet soils as long as they drain well. It is not favored by deer but rabbits will eat this plant. It is easy to grow and rarely needs staking. Anise hyssop is easy to grow from seeds and usually blooms the first year. Plants that spread by rhizomes can also be divided in the spring or fall to make more plants. 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 are easy to move when they are still small. The plants will wilt quickly when they are moved, but they will get better in a few days. To get seeds, let the flower spikes dry on the plants and then either bag the spikes to catch ripening seeds or take them off the plants to get the 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 grows up to 2 feet tall and 15 inches wide and has deep violet–blue flowers and glossy green leaves. Besides A. sylvestris, there are a lot of other species and showy hybrids with pink, orange, or red flowers. foeniculum as a parent. ] Some readily available types of A. foeniculum include:
With its licorice-scented foliage and attractive flowers, anise hyssop (Agastache foeniculum) is a prized herb in any garden. But when and how should you harvest it to get the highest yields? Proper harvesting technique is key to reaping the full benefits of this versatile plant. Here is a comprehensive guide to harvesting anise hyssop for cooking, tea, essential oils, and more.
When to Harvest Anise Hyssop
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For leaves Harvest leaves anytime once the plant is established, Pick leaves as needed once they reach 2 inches long Don’t harvest more than one-third of leaves at a time to avoid stressing the plant,
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For flowers Wait to harvest flowers until they are fully open and vibrantly colored, Snip flower spikes when at least half the flowers on the stalk are fully bloomed,
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For seeds: Allow flowers to fade completely after blooming finishes. Seeds are ready to harvest when flower heads turn brown and dry, releasing seeds easily when crushed.
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For essential oils: Harvest anise hyssop just after the peak of blooming when oil content is highest in the leaves and flowers.
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For drying: Cut anise hyssop stems when at least half of the flowers on the stalk are open. Air dry bundled stems upside down in a dark area.
How Often to Harvest Anise Hyssop
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For leaves: Harvest leaves no more than once per week. Pinching off leaf tips stimulates branching and continuous harvests.
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For flowers: Deadhead spent blooms to encourage reblooming. Cut back whole flower spikes after flowering for a second harvest.
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For seeds: Seeds can be harvested once at the end of season when completely dry. Crush seeded heads in a paper bag to collect.
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For essential oils: Leaves and flowers can be harvested up to 2-3 times per season for distillation. Avoid overharvesting the same plants.
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For drying: Cut flowers for drying only once per season. Remove any dead leaves from stems before drying to prevent mold.
How to Harvest Anise Hyssop Leaves
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Use clean, sterilized pruning shears or scissors to prevent disease transmission.
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Select healthy, vibrant leaves from established plants at least 2 feet tall.
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Cut individual outer leaves near the stem, leaving at least one third of leaves on the plant.
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Rinse and pat leaves dry before use. Refrigerate unwashed leaves in a glass jar or plastic bag for 2-3 days max.
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Leaves can also be frozen, dehydrated, or infused in vinegar or oil. Freeze leaves in a single layer first before storing.
How to Harvest Anise Hyssop Flowers
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Use bypass pruners or floral scissors for harvesting flowers. Sterilize tools between plants.
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Snip off flower spikes when at least half of the individual flowers are fully open.
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For air drying, cut stems 6-10 inches long and bundle 3-4 together. Remove leaves.
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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 essential oils, distill fresh flowers and leaves as soon as possible after harvesting.
How to Harvest Anise Hyssop Seeds
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Allow flowers to fade completely after the final flush of summer blooms finishes.
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Monitor flower heads daily and wait for them to turn brown and crispy when touched.
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Clip off entire dry flower spikes and place in paper bags. Crush the bags to separate the seeds.
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Spread seeds on a screen or sheet to dry further for 1-2 weeks. Discard shriveled or moldy seeds.
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Store thoroughly dried seeds in glass jars in a cool, dark place. Label with plant name and harvest date.
What Parts of Anise Hyssop Are Used?
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Leaves: Used fresh or dried in teas, cocktails, jelly, fruit salads, marinades, etc. Imparts flavor and aroma.
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Flowers: Used dried in teas, potpourri, sachets. Also used fresh in salads.
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Seeds: Used dried as a seasoning similar to anise seeds. Often made into a flavorful essential oil.
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Stems: The stems are not used. Trim off leaves and flowers for use only. Discard woody stems after harvesting.
Proper timing of harvests and using the right techniques ensures maximum flavor, quality, and yield from anise hyssop. Follow these guidelines for successfully harvesting each part of this multipurpose plant. With care, a single plant can provide an abundant supply of leaves, flowers, and seeds year after year.
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