If you asked me to name my top five native plants, I would probably hem and haw and spend a lot of time counting on my fingers. One of them, however, would make the list with no problems—the fantastic genus Agastache.
More commonly known as hyssop or hummingbird mint, boasting a dozen species, the odds are pretty good that if you live in North America, there’s a hyssop near you. They’re nectar plants, first and foremost—large quantities of essential oils in the leaves make them unappetizing to bugs and deer alike. (I hear you can make a nice tea, though, and the flowers are edible.) So they’re not much of a host plant, but as nectar goes, they’re one of the great assets of the garden.
The Agastache you’ll find at the nursery—and these days, you will find a LOT of them!—come in two basic varieties. One is based on or hybridized with A. rupestris, aka “licorice hyssop” or A. aurantiaca, aka “hummingbird mint.” These hail from Arizona and New Mexico. The flowers of both are small trumpets of red and orange, and are pretty indistinguishable, although the leaves of A. rupestris are much narrower.
Photo from US Forest Service, Wikimedia CommonsWhile not native to my area, I have grown these in my garden. (I, uh, might possibly have a teeny little Agastache collection. Small. Wee. No more than twenty or thirty plants, tops.) A. aurantiaca rots in our wet springs, and there’s not much point to it unless you’ve got a REALLY well-drained spot. A. rupestris does much better. Hummingbirds and hummingbird hawkmoths think it’s pretty nifty, and the straight species does okay in the humidity of North Carolina, although it likes a lot more supplemental water than you’d think, and it gets grumpy planted in the vicinity of tree roots.
Most of the cultivars are pretty ho-hum, and don’t improve on the species much, if at all. The only real jaw-dropping hybrid of this one I’ve encountered is Agastache x “Heatwave” (and lord knows what they crossed it with–A. rupestris shows in the flowers, but the leaves look more like A. aurantiaca, and there might be some A. cana or A. mexicana in there, too.) Gotta admit, this is a pretty impressive plant. It shot up five feet in one season, a nicely open, see-through plant, which hummingbirds definitely found interesting. The label said it got eighteen inches tall. The label lies like a rug. Do not trust the label. Had I known that I was going to have a giant, I would not have put it at the front of the border. I should have moved it earlier this spring, but I got distracted by other things, and now it may simply be easier to move the front of the border forward three feet.
The other sort of Agastache you’re likely to encounter are the Big Blue Spiky Things.Agastache foeniculum, photo by Wayne Ray from Wikimedia Commons
The vast majority of these are based on the native Giant Blue Hyssop, A. foeniculum, and man, there’s a lot of ‘em. They have thick columns of tightly packed compound flowers. While hummingbirds like A. rupestris, there’s nothing like A. foeniculum for bees and sundry other pollinators. You’ll rarely see a column of blue hyssop during the summer that doesn’t have at least one pollinator climbing up it.
Giant Blue Hyssop is native to the north of the continent, as far south as Colorado and chunks of New England. While not native to the mid-Atlantic, where I am, we haveA. scrophularifolia (giant purple hyssop) which is nearly identical. (We also have A. nepetoides, giant yellow hyssop, and good luck finding any live plants of that for sale, alas.) There are a few cultivars of A. scrophularifolia, including “Blue Licorice” which are okay, but for the most part, what you’ll find at the nursery are A. foeniculum, either a selection, such as “Snow Spike” or a hybrid with A. rugosa, the only Asian species in the Agastache family.
At a conservative estimate, there are about forty bizillion different blue hyssop cultivars, and they make more every year. I’ll be honest with you, though—once you’ve seen one, you’ve seen most of ‘em, and I don’t recommend laying out large sums for any particular variety, because they’re all pretty darn similar. While there are plenty of plants where the cultivar/nativar/species issue is indeed a significant one, I’ve got a dozen different blue hyssops in the front flowerbed, both the straight species and cultivars, and none of the bugs seem to care much which they’re on. (They do care if you start playing with the colors, though—”Snow Spike” is white and still pretty popular with the bugs, but “Red Fortune” has pink flowers and might as well be made of plastic as far as the pollinators are concerned.)
The “Fortune” series of hybrids are the ones you usually find, with “Blue Fortune” being the best overall, having extremely thick columns of flowers that attract the larger native bees. “Black Adder” and “Purple Haze” are okay hybrids–”Purple Haze” has very narrow wands, interesting to smaller pollinators but not as much to large native bees. “Golden Jubilee,” a selection of A. foeniculum, has shocking chartreuse leaves, but the flowers seem to be identical to the straight species, and the pollinators don’t seem bothered by the leaf color.
The primary difference between the commercially available varieties is in self-seeding. “Blue Fortune” is a sterile hybrid* and thus the flower heads last halfway to forever. (Many of the A. rugosa hybrids have thicker, longer lasting flower columns for just this reason.) A. foeniculum selections, on the other hand, frequently self-seed like the devil. “Snow Spire” is very short lived—by which I mean it lasted all of one season—but left extremely vigorous babies all over the backyard. (I’ll let you know whether they come true from seed.) “Golden Jubilee” did not spread quite so dramatically, but left a line of chartreuse babies in the direct path where I cut down the flower heads. (So much for deadheading to control self-seeding…) The straight species also seeds in, it’s just harder to tell because the leaves, not being screamingly bright green, are not quite so immediately obvious. None of them have proved terribly difficult to control, though—a layer of mulch or a quick yank takes care of them, and they’re so far not inclined to return just because you left a molecule of root stock in the soil. (Although they DO do the thing where you will swear it was bare dirt yesterday, and when you turn around, there’s a foot-high hyssop looking innocent at you. Wily little buggers.)
Obviously if you are working on restoring a natural area, you won’t want a hybrid, and I’d avoid any of the weird color-morphs. In a garden, however, if you’ve got the space, some of the colorful selections can be fun to try. Just be aware that if you provide a congenial environment, A. foeniculum at least will try to fill it.
So! Agastache! A deer-resistant nectar plant extraordinaire! The only problem 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 if you can sneak another in under the paw-paw tree.
*Like really truly, not like “We claim this is sterile and won’t self-seed!” and then you have purple loosestrife growing on the moon. I would have loved it if this plant self-seeded, because the bees couldn’t get enough. It doesn’t, since the sterility is the exact reason the flowers are so awesome. The only way to propagate it is by cuttings. I eventually gave up on it, despite superior flowers, because it would peter out after a year or two and need to be replaced.
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