Very aggressive spreader. As bad as anything in my perennial beds. It does seem to be fairly easy to pull, at least. I'm moving some of it to a wild area, so it can spread to its heart's content, and will probably die in the unamended soil.

It does provide a good opportunity to see the exact difference between honeybees, and bumblebees, and wasps, and hornets, and then there are the little buzzy things, and the bigger buzzy things... and I'm not going to even try to control it until it stops buzzing.

Mad_gallica, do you grow P. muticum or another species? I have read that P. incanum looks similar to P. muticum but is a much more aggressive spreader. Also, what is your soil like? I wonder if they are encouraged to spread in looser, sandy soils?

Yes, the amount of happy insects these plants attract is amazing! Nectar-gathering pollinators are highly unlikely to attack or sting. I have a very small garden with a huge amount of insect traffic due to planting specifically for pollinators and I have never had a problem so far, even when brushing up against the plants or weeding. But you are correct, probably best not to move the plants until they stop buzzing, lol! :-)

This post was edited by ispahan on Mon, Aug 26, 13 at 23:07

Deleted double post...

This post was edited by ispahan on Mon, Aug 26, 13 at 22:34

It was purchased as P. muticum from a reputable local nursery that dealt with some rather to extremely odd things. So it is probably correct.

My soil is heavy and rather clayey, where there aren't rocks. The amended beds, which this started in, have basically had the rocks replaced with manure, and the soil loosened up. It's a fairly dry bed, though, being on a slope. It used to be under a dying white pine, but it fell over last spring. One of the reasons the clump is so large is because it has left the bed. Which means it is heading off into soil that is either rocks or rock hard.

Very good information about this plant, particularly the tip on its potential invasiveness.

It really is a gorgeous looking plant though. I recently saw it on Piet Oudolf's website and greatly admired it.
CMK

Here is a link that might be useful: Mt. Mint in Piet's design

CMK, thank you for the Piet Oudolf link. This plant definitely is a stunner! I can't wait until my own plants mature and fill out a bit more.

I've got 2 Pycnanthemum virginianum, (Virginia Mountain Mint ) 2 P. pilosum, (Hairy Mountain Mint) 1 P. tenuifolium, (Slender Mountain Mint) and 1 Blephilia hirsuta (Hairy Wood Mint). I'm very pleased with all of them. All but the wood mint are in a partially shaded bed that was amended once, 7 years ago, and I only watered them the year they were planted. (The wood mint is in a mostly shady area.) So far -- I planted them last spring -- they haven't wandered. However, I "weed" in the spring (or fall, depending on how many flowers I had to plant in the spring!), by laying down cardboard or several layers of newspaper under my mulch. In any case, if they spread around, I don't mind, as the only other flower in this particular bed is violets, and they can usually hold their own.

I didn't know the mountain mints came in so many different forms. I planted out some p. muticum seedlings this spring and am looking forward to seeing them bloom next year. I did hear the same stories about the way it spreads, hopefully it's an easy weeder like monarda and not a deep rooter/ sprouts from every tiny root hair like some of my favorite pests.
I saw this blog write up on some of the mountain mints if anyone is interested.

Here is a link that might be useful: Hayefield blog with mintyness included

I've grown P. muticum and it's a beautiful plant.* It was invasive enough in full sun and decent garden soil that I had to eradicate it. I've since planted P. virginianum in another spot and hopefully won't live to regret it.

As for ispahan, planting P. muticum in an unpromising, tough situation and having it thrive there is probably a key to contentment with the plant.

*if you planted it en masse next to Sedum 'Autumn Joy' the constant buzzing of bees and other insects enjoying the blooms might get overpowering.

Sounds like I might have stumbled onto a great spot for my Pycnanthemum muticum then! Under a mature silver maple where it is unlikely to do any damage.

I just added in a few more plants to this area so they can start establishing roots before the cold sets in.

Kato, thanks for the Hayefield blog link! I love Nan Ondra's gardening style and taste in plants.

I forgot to say that I was first inspired to plant Pycnanthemum muticum after seeing it at the Lurie Garden (partially designed by Piet Oudolf) in Millenium Park near my home. I might be a bit biased, but I think this is one of the best public gardens I have seen anywhere, bar none. They have vast sweeps of Pycnanthemum planted that buzz with life during peak bloom season.

The link below even includes a short video that shows the great black wasps that have been enjoying my own comparatively meager plants lately. These are enormous solitary wasps that look scary but are completely non-aggressive and show no interest in humans.

Here is a link that might be useful: Pycnanthemum muticum at the Lurie Garden

This post was edited by ispahan on Thu, Aug 29, 13 at 21:43

Here is another blog featuring the incredible sweep of Pycnanthemum muticum at the Lurie Garden:

Here is a link that might be useful: From the Soil: Seeing the Lurie Garden Anew

I've read mountain mints are short lived perennials? I would love to grow if it isn't.

Hmmm...I haven't been growing it for years and years, but it doesn't seem short-lived to me. My clumps are slowly expanding (but not aggressively) and have been looking more robust each season. I am still in love with mine. Such a wonderful, attractive, unique garden plant!

Silver goldenrod,
I bet you can collect seeds yearly and keep a constant supply coming back from year to year. If they are short-lived, nature must make it easy for them to renew, or they wouldn't survive in the wild. I'm thinking the benefit to pollinators is at least worth a try. I was also wondering if anyone has had the idea of collecting seeds from that garden to sell as a revenue stream for the garden, as well as a way to spread the use of beneficial plants far and wide.

Martha

It isn't remotely short lived here. It is rather pushy, though, so it isn't a plant for everyone.

The Lurie Garden is fantastic.

UPDATE:

I unexpectedly came across this plant at a nursery yesterday. It is now home with me.

'ispahan', how did yours do this spring?

I have to chime in that...in nature, those mountain mints are just as described, a buzzing mass of pollinating insects when in flower and they are about the last thing to give up the ghost in a drought. TOUGH!
However, they're not particularly hard to pull up, though I don''t know from personal experience if the roots will reshoot or not. I've never planted it in a garden before, but admired it much in the wild.

I love mine and they are wonderful in mixed flower arrnagments..last forever.

Thanks for that 'shadey'.

Any chance you might have a picture or two of it in your garden?

kind of mixed in with other things..my garden is NOT real neat

another

Thanks for that 'shady'.

I still love this plant! Mine is just beginning to bloom now and the bracts are becoming more and more silvery with each passing day. It is only a matter of time before it becomes buzzing with happy pollinators!

I divided up a clump of it this past fall (September) and planted pieces around my garden here and there, and I was surprised to find that most of them did not make it through the winter, even with the deep, reliable snow cover. My more established clumps made it through just fine and expanded a little from the base. But overall it has certainly not been aggressive by any means (yet)! I also think it is very easy to pull up, yank out and/or transplant when needed.

This is a good post. I winter sowed the Hairy Mt. Mint last winter. I am looking forward to see this plant bloom. Beautiful pictures.

From an area that a number of mountain mints are encountered in the wild, the foliage smell is unmistakable (as is the flower scent). I have always admired the white burst of foliage as it nears bloom, and the rugged conditions it usually grows in (thin, dry soil).

I eventually planted 3 Pycnanthemum muticum last season in part based on the positive posts in this thread. It would be so good if they thrived...we really want to help the at threat pollinators.

and I was surprised to find that most of them did not make it through the winter, even with the deep, reliable snow cover.

UPDATE:

Of the four Pycnanthemum muticum I planted last summer only two have survived :(.

Could it be that they got too wet? Habitat is usually quite dry, esp in winter.

With all the snow melt each spring excessive moisture exists for a time in that location. But I have seen several references to "Mountain Mint" being successful in fertile damp(er) locations?

As you have heard before, damper is relative...and the more barren areas it grows in nature, have good drainage, usually a slope. And....damp in Arkansas or Oklahoma is a lot different than damp in the NE. I'd suggest well-drained in your area.

If the plants were moved in the fall, they might not have had enough time in their new spot to develop adequate roots to get them through the winter. Just a thought.

martha

Yup. I am not too concerned. 2 out of the 4 isn't terrible. It is just that the nursery I had purchased them from is no longer in business :(. These aren't the sort of plants one can pick up at some big box store ;).

UPDATE:

I just realized today that there is no sign of my remaining couple of

"Mountain Mint" :(.

I wonder...if it should be classified as a short lived perennial perhaps ? (Haven't grown it myself)

Rouge, if you were south of the border, I'd mail you some.

I appreciate the offer 'mg'.

I really like this plant.