Native Plant Profile: Mountain Mint (Pycnanthemum spp.)
I first learned about mountain mint (Pycnanthemum spp.) several years ago, as a Penn State Extension study found it to be one of the top pollinator plants in their common gardens. Out of the 86 native plant species and cultivars tested, clustered mountain mint (Pycnanthemum muticum) ranked number one for the diversity of pollinators that visited. I had to try it out for myself, and it hasn’t disappointed.
There are eight species of mountain mint in Maryland, one of which (basil mountain mint) is historical, while three others (Torrey’s, whorled and Virginia) are rare to uncommon. As you may have guessed, mountain mints are in the mint family (Lamiaceae) and sport square stems with opposite, aromatic leaves. Most mountain mints average 1-3 feet in height and have a 1-2 foot spread.
Two species often found in cultivation include clustered mountain mint (Pycnanthemum muticum) and hoary mountain mint (Pycnanthemum incanum). Both species have ovate, toothed leaves with clusters of white flowers at the nodes. When the leaves are crushed, they have a spearmint scent. Mountain mints are relatively deer resistant, but sometimes curious deer will take a nibble of emerging foliage.
Clustered mountain mint grows best in full sun, but it can tolerate part shade too. It prefers moist, well-drained soil, but can live in clay. It has dense flower-like cymes that bloom for weeks in August and September. Like other mints, clustered mountain mint spreads through rhizomes and seeds. It easily can be pulled up if it gets too aggressive.
Hoary mountain mint, unlike its cousin, prefers sunny, acidic soils that are relatively dry. It can tolerate part sun and clay, rocky or sandy soil. It can even withstand drought. Covered with fine hairs, hoary mountain mint leaves appear powdery white. Hoary mountain mint flowers from July through September.
Mountain mints are attractive to many species of insect pollinators, from bees to wasps, flies, butterflies, skippers and beetles. Many of the insects are small in size but are important. Predatory species, like thread-waisted wasps and scoliid wasps, enjoy the nectar as adults and will feed other insects to their young. While mountain mints do produce a lot of seed, birds do not seem to care for them. The flower heads are attractive when dry and can be left up through the season.
Ellis, K. 2013. Identifying and Promoting Pollinator-Rewarding Herbaceous Perennial Plant Species. Final Report to Pennsylvania Department of Agriculture. 16pp.
Hilty, J. 2019. Illinois Wildflowers website. https://www.illinoiswildflowers.info/ Accessed May 24, 2019.
Welcome to Summer!
It seems like spring has quickly blossomed into summer! We are now in peak bloom time for many local plant species, as well as peak activity for local wildlife.
In this issue of HabiChat, you can learn about a lovely group of perennial flowers known as mountain mints, as well as a common backyard snake – the eastern ratsnake. In addition, thanks to Rod Simmons, Natural Resource Manager and Plant Ecologist with the City of Alexandria, I have included a short article on alternatives to traditional lawn.
I am also excited to announce a new Common Snakes of Maryland Photo Guide which covers twelve of the most commonly seen snakes in the state. I also have been busy updating our Snakes of Maryland pages to reflect recent changes in taxonomy.
As summer ripens, check out some of our previous HabiChat articles on topics such as Xeriscaping, Minimizing Pesticide Impacts to Pollinators or Growing Your Own Seed. Don’t forget to add water to your landscapes as well! Finally, keep in mind that deer are currently giving birth. For questions regarding fawns, check out our Deer Fawn page.