Over the last few years I have developed a new appreciation for native plants and watching how they are used by the wildlife. The clustered mountain mint is certainly impressive on that scale.
It drew a recent wave of red-banded hairstreak butterflies (Calycopis cecrops) to the Columbus (Ohio) Botanical Garden, where I work. The red-banded hairstreak is small but absolutely stunning with two tails on the hind wings that always appear to be moving along with colorful eyespots to trick predators. With wings folded, you see broad orange-red bands outlined with white.
Not only has our clustered mountain mint attracted these beautiful butterflies, it also seems that every kind of wasp and bee in the neighborhood finds it a delight.
Known botanically as Pycnanthemum muticum , clustered mountain mint grows from Texas to Maine. Although clustered mountain mint is the official USDA common name, in the nursery trade it is commonly known as short-toothed mountain mint or big-leaf mountain mint.
Don’t let the mint name scare you. It is not invasive like many other mints. This is a taller shrublike plant reaching 3 to 4 feet. It is showy in the garden, looking green, then forming silver-colored bracts with disks that open to reveal small pink blossoms.
The clustered mountain mint is perennial and cold hardy through zone 4, which includes North Carolina. It may be easier to find online or by mail order than at your local garden center unless your garden center specializes in natives.
Once you secure your plants, prepare your soil by incorporating organic matter. The best performance will be in fertile, moist but well-drained soil. Although they will thrive in full sun, with the heat of the day, shade will be appreciated. After you plant, apply a good layer of pine bark mulch to help conserve moisture. You will appreciate that this plant is deer-resistant.
We have ours in raised beds with full sun, and its performance has been awesome. I would probably like it even more if it had a little afternoon shade protection. The silvery sheen from the bracts opens the door for a lot of landscape companions. We have ours partnered with red bee-balm or monarda.
You’ll love it in a woodlands-edge type bed or in an old-fashioned perennial garden. Consider clustering three plants, spacing about 24 inches apart. Try combining with other silver- to gray-foliaged plants such as rose campion, Lychnis coronaria, blue mealy cup salvias like Victoria Blue, or the new indigo spires selection Mystic Spires Blue. It will also partner well with the violet-colored Mexican bush sage Salvia leucantha.