It is only within the past decade that a number of new noteworthy members of the genus Agastache have emerged from botanical obscurity and entered the gardening spotlight. There are a number of standouts that will dazzle gardeners with their copious flowers, statuesque growth habits, and amazingly long seasons of bloom.
Many of the newer selections are from the south-western United States and from Mexico. While the small-flowered species and hybrids, such as anise hyssop, attract butterflies and bees, the large-flowered varieties have co-evolved with hummingbirds as their primary pollinators and have long flowers in shades of orange, pink, lavender-pink, and rose-pink.
Each one has a scent all its own, and the aromatic foliage and flowers are appealing to bees, butterflies, hummingbirds, and gardeners alike. Best of all, they offer colour to the garden in late summer and early autumn, when many gardens are winding down and getting just a little bit dull.
The only problem with Agastache is that if you are inclined to collect plants, they’re very seductive. You start with one, and the next thing you know, you’ve got ten different Agastache in the flowerbed and are wondering where you can find space to sneak another one in.
Agastache rupestris ‘Apache Sunset’ is one of the best, most durable species of all of the Agastache family. It produces compact plants with dozens of sturdy spikes that are studded with gorgeous, tubular coral-peach blooms with rose and violet buds.
With smoky orange flowers held by lavender calyxes, the entire plant is scented like licorice and mint. The elegant spires of bloom and delicate foliage create a haze of colour all summer and into Autumn.
Suitable for the border or grown in containers they are terrific as a cut flower for bouquets. In the garden the bees and butterflies are drawn to their intense coloration and sweet nectar.
Agastache rupestris is known to be one of the hardiest species, avoid heavy clay soils for successful overwintering and wait until earliest spring to cut back. They are drought tolerant once established, but are best if water regularly in their first year.
Compact and quick growing, if given an early sowing, Apache Sunset will flower in the first year from seed. Plant them to add colour, texture, structure, fragrance, and late-season bloom to your garden.
Sowing: Sow February to March or April-June.
Sow early in February-March under glass to flower September-October, or sow April-June to flower June-September the following year. Seed can also be sown directly in the ground in spring.
Sow under cover; sow in warmth to germinate; prick out and harden off in late spring. Or sow direct in autumn when soil is warm. Protect seedlings throughout winter. Likes rich moist soil and full sun.
Sow the seeds into cells or pots containing good quality seed compost. Sow finely onto the surface and press lightly into the compost, but do not cover, as light aids germination of seeds. Place in a propagator or cover with a plastic lid and place in a warm place, ideally at 18 to 20°C (65 to 68°F).
Water from the base of the tray, keeping the compost moist but not wet at all times. Germination 14 to 28 days. Once some of the seeds have germinated air should be admitted gradually otherwise the seedlings may suffer damping off.
Once the seedlings have their first pair of true leaves (they come after the seedlings first pair of leaves) and are large enough to handle, Prick out each seedling into 7.5cm (3in) pots to grow on.
Gradually acclimatise to outdoor conditions for 10 to 15 days before planting out after all risk of frost has passed into well drained soil. Plant 30cm (12in) apart.
To prepare ordinary garden soil for planting, add 5cm (2in) of gravel and 10cm (4in) of compost. Mix in well down to 30cm (12in). Dress plants with gravel to keep water away from crown to prevent rot.
Agastache prefers free-draining soil but tolerates almost any soil and will cope with dry, poor soils very well. They can be grown in full sun but will take some shade if dry. As is typical of many aromatic perennial herbs, a 'tough love' approach works best—full sun and not too much water or fertiliser. In fact, most plants will need little, if any, supplemental irrigation. In dry climates, a deep soaking every week or two during the summer growing season is adequate.
The sturdy plants will usually not need staking, but you may need to do so if planted in rich moist soils or in exposed positions. Although agastache already boasts a very long flowering period, usually until frost, the plants will be stronger and more floriferous if you cut back flower stalks as flowers fade.
Agastache are short-lived perennials, don’t worry too much if your plant keels over after three or four years, you haven’t done anything wrong. They will self-seed where happiest, but this is usually never enough so collect the seed to ensure that you will never be without.
Remember that when different Agastache species and hybrids are planted in the same garden, they will cross-pollinate. Watch for volunteer seedlings, and weed out individual plants that don’t demonstrate desirable habit and flower colour.
A few Agastache species are not reliably hardy, especially in wet winters, but Agastache aurantiaca is one of the hardiest of the species, to around minus 18°C (0°F). Take care when mulching hyssops, especially in wetter climates. In these areas, it is best to avoid mulching materials like composted leaves, lawn clippings, and bark chips since they can encourage the growth of fungal and bacterial pathogens. Pine needles are a better choice, but a few inches of crushed-gravel mulch is ideal.
Cottage/Informal Garden, Flower Arranging, Containers, Borders and Beds.
For cut flowers, harvest when a third to half of the florets have opened.
We do only just seem to be waking up to the herbal essences of Agastache. There are, however, around a dozen different species, some of which earn their place in the herb garden better than others. All have deliciously, spicily scented leaves as well as those lovely smoky blue or purple flowers.
Take one or two and chew them and you’ll freshen your breath with its clean, savory flavour.
Pick young growth and sprinkle in salads, use to decorate cakes or float in drinks. Agastache added to your Pimms lifts it to a higher sphere altogether, or make a tea, the mintier ones, like A. rugosa, often have a better flavour, the crushed leaves smell strongly of mint or aniseed and are often likened to liquorice.
You can dry the leaves for potpourri and also flavour meat, specifically pork, with a uniquely piquant tang, either aniseedy or minty depending on the species you choose.
If you plan to collect seeds, be aware of cross-pollinating; do not place different agastache plants close together.
At the end of the season, each flower will produce four oval-shaped nutlets containing dark, tiny seeds. Allow them to dry on the stem, collect in paper bags, remember to label and sow in spring or in autumn.
The genus Agastache has about 3,500 species worldwide, many of them ornamental and economically important for their essential oils.
About 30 species are native to North America and Asia. Agastache rupestris is native to the southwestern USA and can be found from the mountainous regions of southeastern Arizona, southwestern New Mexico, and northern Chihuahua, Mexico.
The genus name is related to the flower clusters. Agastache, from the words agan, meaning ‘very much’ (or ‘many’) and stachys, ‘an ear of corn or wheat’ referring to the shape of the flower spikes, so meaning ‘having many spikes’.
The species name is from modern Latin rupestris meaning ‘found on rocks’ or ‘found among the rocks’. It derives from the Latin rupes meaning 'rock’.
Members of the genus Agastache are often called 'hyssops', but this name is a poor choice because these plants have little in common with the true hyssop (Hyssopus officianalis), which is a Mediterranean herb with both ornamental and medicinal value.
The plant has a number of common names, many of which include the name 'hyssop'. It is most often referred to as the 'Sunset Hyssop' in reference to the resemblance of the flower colours to the hues of a sunset.
The name Rocky Giant Hyssop refers to the origin of the plant, while the name Thread-Leaf Giant Hyssop refers to the fine foliage. The names Licorice mint and Licorice hyssop are in reference to the minty-licorice-root beer aroma of the foliage.
- Additional Information
Packet Size 20mg Average Seed Count 30 Seeds Family Lamiaceae Genus Agastache Species rupestris Cultivar Apache Sunset Common Name Sunset Hyssop Other Common Names Licorice Mint, Sunset Hyssop, Rocky Giant Hyssop or Thread-Leaf Giant Hyssop Hardiness Hardy Perennial Hardy Down to -18°C (0°F) Flowers Smoky orange flowers held by lavender calyxes Natural Flower Time July to September Foliage Fragrant mid-green oval leaves Height 80 to 90cm (20 to 24in) Spread 30 to 45cm (12 to 18in) Position Full sun for best flowering Soil Reasonably fertile, moisture retentive but well drained soil