Blunt mountain mint (Pycnanthemum muticum) is not considered invasive like other types of mints such as spearmint or peppermint (Mentha species). While true mints are notorious for their aggressive spreading behavior, blunt mountain mint is relatively well-behaved in the garden. It does have the ability to slowly spread through underground rhizomes, but it is not overly invasive.
Unlike its mint relatives, blunt mountain mint does not have a tendency to take over and dominate the garden. Its spreading habit is much more controlled and manageable. However, it is still important to keep an eye on its growth and prevent it from spreading too much if desired.
One effective method to control the spread of blunt mountain mint is by cutting off the underground rhizomes with a spade. By severing the rhizomes, you can limit its expansion and prevent it from encroaching on other plants or areas of the garden. This can be done annually or as needed to keep it in check.
I have personally grown blunt mountain mint in my garden for several years and have found it to be quite well-behaved. It has slowly spread over time, but I have not experienced any issues with it becoming invasive or overwhelming other plants. I have occasionally used a spade to cut off any rhizomes that were venturing into unwanted areas, and this has effectively controlled its spread.
In terms of its growth habit, blunt mountain mint forms clumps of upright stems that reach a height of about 2-3 feet. It produces small, white flowers that attract pollinators like bees and butterflies. The foliage has a pleasant minty fragrance when crushed, and it can be used for culinary purposes or in herbal teas.
While blunt mountain mint does have the potential to spread slowly through rhizomes, it is not invasive like true mints. With proper monitoring and occasional rhizome cutting, its spreading behavior can be easily controlled in the garden. Its attractive flowers, pleasant fragrance, and ability to attract pollinators make it a valuable addition to any landscape.
