(Editor's Note: This article was originally published on June 27, 2011. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
In official terms, Agastache is a member of the Lamiaceae family, making it a cousin of mint. However, Agastache isn't plagued with the sprawling invasiveness of that popular herb; it is instead a quite well-behaved, upright plant that flowers through summer and into fall, if properly maintained.
However, adding confusion to identifying agastache species is that it is sometimes referred to as "mint" or "hyssop" in the name. For example, Agastache cana is also known as Texas Hummingbird Mint or Wild Hyssop or Mexican Hyssop. Looking at the Latin name will never steer you wrong in this case, though; regardless of the common name, Agastache will always be there.
Let's examine some of the more popular cultivars of Agastache, a few of which are relatively new:
Blue Fortune - One of many agastaches known as Anise Hyssop for their distinct licorice scent when crushed, this hybrid of A. rugosa and A. foeniculum has been around for ages, and with good reason. It's long, lavender gayfeather-like flower stalks seem to last forever and add a wonderful vertical element to the garden. (High Country Gardens, an online retailer that carries a large number of Agastaches, recommends this cultivar for those gardening in the wetter winter conditions of the Midwest and East.)
Black Adder - Most likely named for the thick black snake and not the hilarious British comedy series, this is one of my favorite Agastaches due its bi-color beauty. The dark purple bottlebrush gives way to lighter purple flowers on the outer layer.
Acapulco Salmon & Pink - Another bi-colored beauty, with stunning orange and pink flowers. This one flowers in a much more sage-like way, however, as do many other Agastache types. (Remember, salvias are also members of the mint family, so the resemblance makes sense.) Hundreds of tiny tubular flowers appear on several long spikes above the bushy plant.
Summer Love - Brilliant magenta and fuchsia flowers. Trust me; the hummers will not leave your yard once they've spotted this one!
Texas Hummingbird Mint - This afore-mentioned favorite is a garden must-have for my area of the country. When nothing else can take day after day of 100° and very little rain, this scarlet red, bushy hummingbird magnet thrives.
Desert Sunrise - A gorgeous orange and pinkish/purple hybrid combo that High Country Gardens founder owner David Salman discovered in his garden a few years ago. In fact, David admits Agastache is an obsession of his, and he has developed several new introductions in recent years.
Several other hybrids have different color variations or even, in some cases, different scents. For example, ‘Root Beer' Agastache smells just like the foamy soft drink. Conversely, ‘Champagne' doesn't smell like bubbly, but it does have a gorgeous combination of yellow/pink flowers.
As for care, fussing over an Agastache is the worst thing you can do. Of course, newly-planted specimens should be given adequate water while getting established, but after that, an occasional trimming of fading flower spikes is all that is needed. Placing on a hot, sunny slope in lean soil is ideal.
If crowded and/or overwatered, Agastache will offer complaint by developing powdery mildew and/or not flowering much. A soggy Agastache may not even make it through the winter. Gardeners growing in regions that get less than 40" of rain a year will probably have the best luck with getting Agastaches to return. Amending the soil with expanded shale or gravel will allow for sharp drainage, which is a "must" with this plant.
In mid-spring, cut back the old foliage nearly to the ground. This should reveal new growth developing in a mound at soil level. Fertilizer is usually not necessary, although it is never a bad idea to work a couple of handfuls of compost around the plant as flower stalks develop.
So, plant some gorgeous varieties of Agastache and put the welcome mat out for hummingbirds...they won't be late for supper!
‘Black Adder' - DavesGarden.com member KevinMc79
‘Desert Sunrise' - DavesGarden.com member plutodrive
‘Hummer and Texas Hummingbird Mint" - DavesGarden.com member greenorchid