This perennial herb or ornamental is confusingly commonly known as anise hyssop, although the plant is neither part of the hyssop species, anise seed, or a star anise. In fact, it is part of the mint family and has many semblances to the mint plant, including its square stalks and toothy dull green foliage with paler undersides.
The plant has an upright habit, growing in clumps of between 2 and 4 feet in height. The anise hyssop produces pretty flowers on tall spikes for an extended period, in shades ranging from white to blue, and purple. It is cultivated in borders and flowerbeds for its ornamental beauty, but can also be grown in herb gardens as it is edible.
The flowers themselves are edible and can be used to garnish salads and desserts, while the stalks and leaves of the plant can be used to flavor foods and brew tea. The scent and flavor of anise hyssop are similar to licorice or aniseed, which is probably in part how the plant earned its common name, although many people claim the plant has more in common with the taste of basil or tarragon.
The scentless flowers of the plant are particularly attractive to bees, butterflies, and hummingbirds.
Anise Hyssop Overview
|Scientific Name||Agastache foeniculum|
|Common Names||Anise hyssop, blue giant hyssop, lavender giant hyssop, fragrant giant hyssop|
|Height||Up to 4 feet|
|Light||Full sun to partial shade|
|Watering||Moist to dry soil|
The International Herb Association has named anise hyssop as the 2019 Herb of the Year (Penn State University Extension). However, when it comes to growing your own aromatic plant, there are many varieties to choose from, with different cultivars ranging in height, hardiness, and flower color. Some even feature unusual foliage to add further interest to their ornamental quality. These include the following.
This is an award-winning plant with striking foliage in an almost neon shade of yellow lime, which is especially vibrant during spring. The flowers of this anise hyssop are purple, providing a perfect contrast against the background of the golden leaves.
This variety of anise hyssop produces fresh white flowers and grows to a typical height of 3 feet.
Another white flowering variety, this herb produces a sparser plant than most anise hyssops, giving a less dense and bushy appearance.
This variety is a hybrid between Agastache foeniculum and Agastache rugosa, created by a grower in the Netherlands. It grows to around 3 feet tall, producing large leaves and chunky spikes of baby blue blooms. The plant is sterile, meaning it cannot produce seeds. While this means that you won’t be able to grow more of the plant from its seeds, it does mean a longer blooming period is guaranteed. This is a popular variety that won the 2003 RHS Award of Garden Merit.
This is another hybrid, producing pretty pink flowers. Though attractive as an ornamental, this variety is notedly less attractive to bees and butterflies than other types of anise hyssop.
This award-winning variety closely resembles the lavender plant, with its deep purple flowers sitting in 5-inch clusters on top of tall spikes. It grows to between 2 and 3 feet in height and is suitable for growing in both borders or container gardens.
Caring for Your Anise Hyssop
Anise hyssop will tolerate a wide range of watering techniques, so long as it is grown in well-draining soil. The plant is drought-tolerant once mature, though it will also thrive in moist soils.
To prevent root rot, work in some sand or grit to your soil before planting anise hyssop to encourage good drainage. Well-draining soil will allow excess water to drain away from the plant's roots, preventing it from sitting in soggy, waterlogged soil, and therefore lowering the chances of the plant developing root rot. Aside from ensuring the soil is well-draining, the plant does not have any other soil requirements and will grow well in a variety of soil types.
Throughout winter, you should not need to water your anise hyssop and instead can rely solely on rainfall to provide adequate moisture to the plant. During spring and summer, water the young anise hyssop plant moderately, remembering to cut back in the event of rain to prevent overwatering. Established anise hyssops will not need to be watered except in the event of long periods of drought, as these plants typically thrive in dry conditions, though they will benefit from occasional water.
Anise hyssop thrives in both full sun and partial shade. It will grow well under the canopy of a taller tree that offers some shade or in open meadows where it experiences full sunlight all day long.
Although this plant loves the sun, it isn’t so keen on extreme heat, so if you do plant it in partial shade, try to position it so that it receives sun in the morning, and is shaded in the afternoon. This will offer the plant some relief from the sun during the hottest part of the day when the shade will grant some heat protection by lowering the temperature by a few degrees.
Anise hyssop can also be grown in a container, so you could experiment with different positions within your garden by moving the container around until you find a spot where the plant is at its happiest.
This plant is hardy through USDA growing zones 4 to 8, but some varieties are appropriate for growing in zones 9 and 10.
The flowers of the plant appear in June, and if deadheaded will continue to bloom until the first frost in fall. Some varieties of the plant are frost tender and will die back during cold winters, but grow back from the roots the following spring. However, there are some types of anise hyssop, which can grow as annuals in cool climates, with the ability to survive in temperatures down to 10 ºF. Mulching the soil on top of the plants will go a long way to ensure their survival in low temperatures, as the mulch works to insulate the roots and protect them from freezing.
Anise hyssop self-seeds easily, so if you refrain from deadheading some of your flowers once they are spent, you will likely find that you have a new patch of anise hyssops appearing the following spring from seeds that have dropped. If you prefer not to have spontaneous anise hyssop growing, make sure to remove all spent flowers from the plant in fall to prevent the seeds from settling in the ground.
To grow the plant from seed, you can start early by sowing the seeds indoors and transplanting them outside when they are seedlings, or you can plant seeds directly in the ground outside. Anise hyssops usually bloom in their first year, so the advantage of sowing the seeds early is that you will have flowers sooner than if they were sown outdoors.
To sow seeds, whether it be inside or outside, simply sprinkle the seeds on the soil and keep them moist. These seeds need light to germinate, so don’t cover them over with soil, and if sowing indoors, then make sure you place them in a well-lit environment.
When the seedlings are young, they will need plenty of water to develop, but once a strong root system has developed, you can cut back on the watering. Thin out seedlings to allow the strongest plants space to grow, and remove any weeds growing nearby as these can inhibit growth. Once mature, these plants can also be propagated by division (Royal Horticultural Society).
Anise hyssop can survive without any pruning at all, so if you are a lazy gardener, then you don’t need to worry about pruning this plant. However, pruning can be beneficial if you are interested in it. In early spring, prune back the stems of your plant, as this will encourage bushier growth in the growing season, resulting in a denser and healthier looking plant.
After spring has passed, refrain from pruning with the exception of removing any dead or damaged stems, as this can cause damage to the plant. In summer, deadhead the plant by removing the spent flowers, as this will encourage further blooming and extend the plant's flowering season.
In winter, many anise hyssops will die back. At this point, you can cut away all of the brown dead growth, as this will make for a much neater appearance, and it will also help the new growth to look its best when it arrives the following spring. However, this winter pruning is purely for aesthetics and will make no difference to the health of your plant, so it isn’t necessary and essentially comes down to personal preference.
Some people like to produce cut flower bouquets from the plant, in which case you can make these cuttings any time during the blooming period. Anise hyssop also makes good dried flowers.
Which variety of anise hyssop do you like best? Let us know in the comments, and don’t forget to share this page with other who may be interested!