Here’s a hard-working, easy-care perennial too few gardeners utilize. Fortunately the nurseries are pushing hard to get it better known, and breeders are bringing out new hybrids in more colors every year.
Hummingbird mint is also known as anise hyssop. It’s often referred to at nurseries by its latin name agastache. (I will call it agastache.) This intriguing plant is deer- and rabbit-proof, blooms June to fall, resists most diseases and provides sustenance for pollinators. A member of the mint family, it does well in most any sunny garden, yet never spreads, reseeds, or gets out of hand.
What’s not to love?
Once you’ve grown it you’ll see why agastache, especially the tall varieties, is the new must-have. Certainly no native bed is complete without it. In fact, agastache is an edible North American native of our plains and prairies, comprising 22 species. Most get 3 to 4 feet tall and prefer sunny, dry conditions. Hybrids though, are often much shorter and do fine under normal garden conditions.
Native or not, every garden needs at least a few of these aromatic-foliaged cultivars. Once you have one, you’ll want more… more color, more billow, more anise scent, more buzz!
When we think of pollinator magnets we rarely think of hummingbird mint. Yet everything loves this plant: hummers, honeybees, moths, butterflies. Their tiny florets open successively over a very long period, making pollinators happy for weeks on end. I even find empty monarch chrysalises on agastache stems.
The biggest challenge Pennsylvania gardeners have with agastache is getting it to survive over the winter, even though it’s rated as hardy in zone 6. I would say most cultivars do well in milder winters and years with good snow cover, but often perish under harsher conditions.
Luckily, one cultivar will survive multiple years in our area. That would be Blue Fortune. It’s my go-to recommendation for both reliable hardiness and exceptional pollinator activity.
Blue Fortune has an open, airy habit and reaches 36 to 50 inches tall, with “bottlebrush” terminal flowers from midsummer to fall. Foliage is upright with opposing leaves. Individual plants can be substantial, with racemes forming at the end of every branch tip. The flowers are a light lavender-blue.
Two other “blue” hybrids are Blue Boa and Black Adder. Blue Boa has fat magenta-violet flowers while Black Adder has slim racemes. (Little Black Adder is a dwarf of the same.)The color is a soft gray-blue to purplish blue in cooler temps. Purple Haze is a rather weak lavender color that pollinators just love. Simply place it with strongly colored companions.
I’ve grown Black Adder and Purple Haze but not Blue Boa. I’ve lost Black Adder over the winter several times, but it is beautiful, especially in the fall. Blue Boa can be hard to find. There are new cultivars coming on the market all the time claiming similar habits, so you’ll have to experiment.
Ava’s Hummingbird Mint from High Country Gardens is a tall pink, with fluted florets arranged all along the upper stems. This 3-foot beauty has been around for at least twenty years and deservedly so. Its billowy clouds in late summer are simply captivating, especially when paired with anemones, phlox or asters.
Unfortunately I lost all of my Ava’s save one this past (wet) winter, after multiple years of great performance. So I recommend it with caution. With our climate becoming more volatile it’s hard to predict what will survive from year to year.
Desert Solstice is a new pink variety, also from High Country Gardens. I decided to try it as a replacement for Ava’s and see if it handles our winters any better. The flowers in the photos look very densely packed, giving it a robust appearance. 2022 is its first summer and it has yet to bloom, so I’ll provide an update later.
2022 update as of October 15: Desert Solstice was acceptable and is still in bloom, but the flowers are delicate and much more sparse than I’d hoped, not nearly as full as the photograph below. Ava’s performed better for me. I will go back to Ava’s. It simply has more presence.
(photo courtesy of High Country Gardens)
2023 update, August 23: Another cultivar disappointment this year was Rosita, a rose agastache with supposedly 50% more blooms than most. Mine did poorly, although it did produce flower spikes. While it’s supposed to reach 24 inches tall, mine never topped 12 inches and the flowering was sparse. The bees are not interested either. So leave this one to Southwest gardens. Not recommended for zone 6 Pennsylvania.
Height Matters
When buying agastaches be sure to check the height. Many orange, pink and red cultivars top out at just 12 to 15 inches tall, with fingernail-sized leaves. Their flowers resemble salvias, with tiny flutes distributed all along the upper stems. While these selections make good low border plants, they need to be massed for impact.
Not all the warm colors are short. Coppery orange Firebird is 36″ tall. I might try this pretty cultivar with helenium and coreopsis next year.
I’m also trialing Kudos Red, even though I’m not a fan of red flowers generally. A petite ten inches high, it’s already covered in tiny bright red blooms. It will be interesting to see if the pollinators like it. So far, there’s been no observable action.
UPDATE as of July 10, 2022 — I would save Kudos Red for a patio pot, windowbox or walkway border. My two plants are healthy but simply don’t have enough volume or oomph to make an appreciable impact unless you get up close. The color is good but they still get lost among the other plants. No pollinators have come either, at least when I’ve observed. It would look fine in a pot, though, remaining petite all season, and it does flower over a long period.
Care and Siting
Agastaches insist on excellent drainage with gravelly to loose loamy soil. Mix in grit or sand and keep the crown just above the soil line. Place in full to mostly sun. Blue Fortune can handle a few hours of shade, but six hours of sun is mandatory. There’s no need to fertilize.
Survival Tip: According to several breeders, leaving the entire plant standing, or as much stem as you can tolerate over winter helps with survival. Mulch after the ground freezes. In spring clear away the dead matter without disturbing the crown. Agastaches are very slow to break dormancy, so be patient — don’t yank out that dead-looking crown just yet! New shoots emerge quite late.
Companion Plants
Because taller agastaches can get leggy by season’s end, they need companion plants to shine. They make excellent companions for native beds and with other tall, informal perennials.
Blue Fortune, Blue Boa, Black Adder, Purple Haze and Ava’s all work nicely paired with veronicastrum, asters, fall anemones and shorter grasses like Shenandoah switchgrass. They also play well with lilies, phlox, coneflowers, rudbeckia and daisies. Annual cosmos, zinnias, verbena and dahlias are some other ideas. I use several varieties with Culvers Root (veronicastrum).
Consider putting at least one agastache next to butterfly weed or milkweed just for the monarchs. They appreciate agastache’s sturdy stems for hanging their crysalises. (They rarely use milkweed for this.)
If your plant is located where you see it frequently, a light trim is a good idea by late summer. Agastaches can tatter and develop “bare feet”. Lower companion plants will help disguise this. Be sure to allow for good air circulation; yellowing, leaf spots and mildew can all afflict agastache, especially in wet, humid or excessively hot temperatures.
Shorter cultivars stay tidier. They work best along walkways, in rock gardens, to the front of borders and atop stone walls. The shortest can even go in pots (which you can store in the garage, plant and all, over winter). Do keep potted specimens watered if they’re in direct sun, as the hybrids aren’t especially drought-tolerant.
If you haven’t tried agastache before, why not give it a try? Its bee-busy blooms are so heartening when the rest of the garden is on siesta, or let it play a supporting role to everything else. The only reason I don’t give it five stars is because of its unreliable hardiness.
I intend to grow agastache for as long as I’m able to keep them thriving. The bees and butterflies deserve it!
