How to Grow Agastache

Agastache plant with purple flowers budding on top of flower spike closeup

The Spruce / Adrienne Legault

In This Article

While tricky to pronounce ("ah-GAH-stuh-kee"), this prolific herbaceous perennial with over 22 different species is well-loved for its ability to lure pollinators. Among these species are plants with more familiar, descriptive names: anise hyssop (Agastache foeniculum), licorice mint (Agastache rupestris), and hummingbird mint (Agastache cana). The name "agastache" is derived from the Greek and essentially means a very large ear of grain, referring to the abundant flower spikes. In addition to being a beneficial garden plant, agastache is also beautiful, available in a wide range of vivid colors from light pink to deep purple, blue, red, orange, and white. It has a minty, herby fragrance and can be dried to make a delicious herbal tea.

Native to most of North America, it also has origins in Asia and South America. The most commonly grown type, hummingbird mint (Agastache cana), is indigenous to the southwestern United States and Mexico and is suitable for xeriscape gardens, with its tolerance for the heat and drought of arid climates. Other types are more tolerant of temperate growing conditions, so you may wish to research the different varieties to find out what is best suited to your environment.

Agastache is deer and rabbit resistant, and a veritable magnet for bees, butterflies and hummingbirds. It's also a fairly long-blooming perennial, offering vivid color for weeks in summer. It is a close relative of catmint, another pollinator-friendly flowering perennial.

Botanical Name  Agastache rupestris, Agastache foeniculum, etc
Common Name Giant hyssop, hummingbird mint, licorice mint
Plant Type  Herbaceous perennial 
Mature Size  3 to 5 ft. tall
Sun Exposure  Full sun
Soil Type  Lean soil, well-drained 
Soil pH  Slightly acidic
Bloom Time  Summer 
Flower Color  Various (blue,purple, red, orange, pink, white)
Hardiness Zones  3 to 10 (USDA) (depends on variety)
Native Areas  North America, Asia, South America

Agastache Care

Like many cottage garden perennials agastache is a prolific grower and reliable for its seasonal color and fragrance. However, because of its desert pedigree, agastache will not grow very well in overly rich or fertile soils, which are often a hallmark of the cottage garden. For this reason, including agastache in a cottage garden setting means planting it in its own separate section alongside other similar plants that like growing conditions with lean soil. These might includie sedum, bearded irises, Russian sage, and black-eyed susan. Cutting back spent flower spikes will encourage reblooming and more growth during the bloom season.

Agastache plant growing flower spikes with tiny buds and leaves on thin stems

The Spruce / Adrienne Legault

Agastache plant with flower spike and tiny purple flowers budding on thin stem

The Spruce / Adrienne Legault

Agastache flower spike with purple flower blooming and buds closeup

The Spruce / Adrienne Legault

Light

Agastache likes full sun and can easily tolerate the hottest sun of the day, so keep this in mind when deciding where to plant it.

Soil

This desert plant grows best in lean soils with low levels of nutrients. Adding a bit of sand to loamy soils can improve their suitability for growing agastache.

Water

Though it enjoys a deep watering, consistently moist conditions are not suitable for agastache. Watering routines should ideally follow desert conditions: occasional blasts of heavy rain followed by days of hot sun.

Temperature and Humidity

Agastache can handle high temperatures better than many garden plants, so it's perfect for that spot that gets strong afternoon sun. Humidity isn't suitable for agastache and growing it in a persistently moist spot will probably cause its roots to rot and its leaves to yellow. It's also important to make sure the roots of the plant stay dry in winter, especially if growing in USDA zones 5 or 6. Placing some gravel around the base of the plant as a sort of mulch barrier can help prevent root rot from frozen soil that defrosts slowly in spring.

Fertilizer

Agastache has no need of extra fertilizer but a top dressing of compost in autumn will keep it healthy.

Varieties

  • 'Blue Fortune' is a European hybrid, with soft periwinkle blue flowers. This variety can also withstand a bit more rainfall and is very cold hardy (USDA 4-10).
  • 'Licorice Mint Hyssop' is a hardy and strong variety with soft orange colored flowers contrasted with dusty purple calyxes: an unusual and gorgeous color combination. The fragrance combines licorice and mint, a real feast for the senses. Also known as "threadleaf giant hyssop."
  • 'Agastache Cana' blooms abundantly with soft rose pink flowers (USDA 5-10). It does well in containers and has a long blooming period from early summer to late autumn.
  • 'Agastache Firebird' is a powerhouse of color, with its grey-green leaves and coppery orange flowers that attract hummingbirds.
  • 'Agastache Honey Bee Blue' is a classic variety with soft bushy flower spikes of pale lavender blue and slightly larger leaves of bluish green.

Propagating Agastache

To grow agastache from cuttings, use pruning shears to remove 6 to 8 inch pieces of green stem in late summer or fall. Strip off lower leaves and lightly scrape the exposed stem with a sharp knife. Dip the scraped portion in rooting hormone and place the stems in a small pot containing a sterile mix of perlite and sand. Water gently and cover with a large plastic bag or humidity dome. Check for root growth in 2 to 3 weeks by gently tugging on the stem. Keep the soil slightly moist and remove the cover when new leaves begin to sprout.

Growing Agastache from Seed

Once established, agastache will spread fairly vigorously in the garden. It can be divided yearly or as needed. Agastache seeds need cold stratification to grow, so the best method is to direct sow them in the garden in the fall, so they are exposed to the winter cold temperatures. Press seeds gently into loosened soil surface, then moisten them every few days in the fall; if your region gets winter snow this will give them enough moisture to germinate in spring. If your winters are dry, occasional light watering of the seeds will help them to sprout when the spring temperatures warm up.