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Rain Garden Plants: Clustered Mountain Mint

An informative guide with details and pictures of Clustered Mountain Mint (Pycnanthemum muticum).
Updated:
June 24, 2026

Two-lipped tubular white to pink flowers grow in flat, terminal clusters. Flowers bloom for up to 10 weeks. Has dense leaves that are aromatic when crushed. Leaves are opposite, broad toothed, and ovate. It is bright green in early spring, turning darker green in summer. Grows fast and can grow in shallow soil. Prune roots in spring with a spade to keep clumps from spreading. Attracts bees, butterflies, and other pollinators. Deer and rabbits avoid it because of the mint aroma.

  • Height: 24 to 36 inches
  • Bloom color: White to pink
  • Bloom time: June to August
  • Hardiness zone: 3 to 9
  • Salt tolerance: N/A
  • Spreading habit: Rhizomes, clump-forming
Close-up of leaf on square stem.
Leaves. Photo by Jodi Sulpizio, Penn State Extension

Site Conditions

  • Sun: Sun/partial shade
  • Soil: Well-drained soil
  • Hydrologic zone: Moist/dry, drought tolerant
New growth.
New growth in spring. Photo Jodi Sulpizio, Penn State Extension
Clustered Mountain Mint. Photo Jodi Sulpizio, Penn State Extension
Clustered Mountain Mint. Photo Jodi Sulpizio, Penn State Extension
Clustered Mountain Mint. Photo Jodi Sulpizio, Penn State Extension
Clustered Mountain Mint. Photo Jodi Sulpizio, Penn State Extension
Clustered Mountain Mint. Photo Jodi Sulpizio, Penn State Extension
Seeds. Photo Jodi Sulpizio, Penn State Extension
Clustered Mountain Mint. Photo Jodi Sulpizio, Penn State Extension
Flowers. Photo Jodi Sulpizio, Penn State Extension

Sources

Clemson University

North Carolina Extension

Prepared by Jessica Chou, Jodi Sulpizio, and Constance Schmotzer.

For a printable PDF version of this article, contact Jodi Sulpizio at jrb143@psu.edu.

Constance Schmotzer
Former Master Gardener Coordinator
Pennsylvania State University
Jessica Chou