Sunday, July 6, 2014

Pycnanthemum - A Hot Summer Pick

There aren’t many plants that start blooming in the hot summer months. Pycnanthemum (pick-nan-the-mum) does and it is definitely one that you should pick to have in your garden!

Pycnanthemum tenuifolium in my garden with small bee

Pycnanthemum is a genus of perennial plants endemic to North America (that is, native only here). The common name is mountain mint (or mountainmint depending on how you spell it). Native throughout the eastern and central states, this genus has a fair number of species to be found in Georgia. The genus is part of the mint family (Lamiaceae) and, not surprisingly, the foliage is aromatic, sometimes very strongly so.

Pycnanthemum incanum at Amicalola with small bee
Until the plants flower, I don’t think most people would notice them. Their “plain Jane” appearance and the tendency of some species to spread by runners would probably land them squarely in “weed” territory for some people even. Once they bloom, however, they literally come alive as pollinators flock to their tiny flowers.

What appears to be a single flower to us is a cluster of tiny individual flowers. Many plants also have bracteal leaves that are whitish in color, creating an even stronger appearance of one large flower.  I am always amazed at the variety of insects that these flowers attract.

Pycnanthemum incanum in 2010
Several years ago I found a large stand of P. incanum on the side of the road that was delighting a group of Eastern tiger swallowtail butterflies. I have also seen the flowers visited by wasps and bees. There is always someone on the patch of P. muticum in my garden.

[By the way, appreciate your wasps - they are carnivores, catching other insects to feed to their young so they are considered beneficial insects.]
Pycnanthemum muticum and medium sized bee

I recently added narrow-leaf mountainmint (P. tenuifolium) to my garden. I got it from an authorized GNPS rescue site that had a hot, dry area. The finely textured foliage gives it a very different appearance. It does not have the extra bracteal leaves, but the flowers are unmistakably mountainmint. P. incanum is found in the shadier edges of the same site.

Pycnanthemum tenuifolium habit, shorter than the others
So if you're looking for more summer flowers to support pollinators (and enjoy yourself), pick Pycnanthemum to add to your sunny spot. By the way, deer don't bother it - a real plus for me!


  1. This is my first year for having mountain mint in my garden and it's just beginning to flower. You've reminded me that I need to station myself nearby, camera in hand, to see which insects it's attracting.

  2. Thanks for your timely post. I have a good patch of Mountain Mint growing in Decatur, from a plant I bought at a GNPS sale a few years ago. We also have some growing in a power easement near our NC cabin. But I noticed last week (in NC) and wondered about a similar plant I don't remember having seen before. It looked pretty much like the Mountain Mint with which I am familiar but without the whitish leaves (or bracts, as I've just learned). Also, it has a different smell which I thought to be something like menthol. Thanks, again, for your informative posts.