In the Garden
Ralph Purkhiser, Purdue University Master Gardener
The Perennial Plant Association has announced that Pycnantheum muticum is the 2025 Perennial Plant of the Year. The association is a group of plant breeders, nurseries, university researchers and botanical garden staff members who share an interest in perennial plants for the landscape. The selection process allows members to submit nominations for the award, which are narrowed down to four final candidates. The members then vote for the winner. Unlike many “plant of the year” selections, the Perennial Plant of the Year is not one of those new and improved plants. Instead, it is a plant that may be grown in a large area of the country and that has shown garden usefulness over many years. This year’s selection is actually native to a large portion of the country.
Commonly known as clustered mountain mint, it is not a true mint and it is not limited to mountainous areas, but its growth habit is clustered. It is a tough, adaptable plant commonly found in meadows and open woodlands in many areas east of the Rocky Mountains. It is cold hardy in zones 4 through 8. It prefers moist areas, but, once established, will survive hot weather and drought.
If you are a gardener who likes plants to stay in one area, surrounded by mulch, this is not the plant for you. Like true mints, to which it is related, clustered mountain mint will spread by seeds and running roots. Its growth habit is spreading and it is best used to mix with taller plants that have more significant blooms or dark foliage. It is great as a living mulch that will shade out weeds. The minty scent and somewhat fuzzy texture of the foliage also serves to make the plant less palatable to deer and other foragers.
The blooms of clustered mountain mint are nondescript. That is not to say that the blooms are unimportant. When the small white or pink flowers open, small bees and other pollinators will be there to seek the nectar. More noticeable than the blooms are the silvery bracts that surround the actual flowers and persist long after the flowers are gone. The bracts and gray-green foliage serve as a great contrast for plants with burgundy foliage, and make a long-lasting cut foliage when combined with large, bright-colored flowers in vase.
Like many perennials, clustered mountain mint benefits from the Chelsea chop. In fact, this plant may be sheared back after each bloom period to create a more-compact plant and encourage another round of blooms.
I cannot remember having ever seen clustered mountain mint at a local nursery. You are more likely to find it as plugs from a native-plant nursery, or order some seeds and give winter sowing of native seeds a try. Having been selected as the Perennial Plant of the Year, it will likely be more available this year.
I noticed some hellebore buds when I returned home from a short trip on January 1. The next day, I took another walk in the garden and found three hellebores in bloom. This is not unusual, and these were in a clump of Helleborus niger, known as the Christmas rose. They will be fine once the snow melts. The snow acts to insulate garden plants, so just enjoy the beauty it brings to the garden. Stay warm and safe.