Slender-leaf Mountain Mint

The 2019 North Carolina Botanical Garden Wildflower of the Year, Pycnanthemum tenuifolium (Zones 4–8), is a fine-textured, clump-forming perennial that provides a unique "airy" aesthetic to the managed landscape. Unlike its broader-leaved relatives, this species features needle-like, silvery-green foliage that remains clean and upright throughout the growing season. In mid-to-late summer, it is topped with dense clusters of small white flowers, often speckled with purple, which create a distinct "frosted" appearance in the garden.

In the NC piedmont, this species is one of the most significant High-Volume Nectar available. It provides high-volume nectar that supports a massive diversity of beneficial insects, including native bees, the Great Black Wasp (a docile beetle-hunter), and various Checkered Beetles. It is a documented Specialist Host for the Gray Hairstreak butterfly.

It has been recognized as a top performer in native plant trials for its extreme drought tolerance and "no-flop" habit.

Performance & Site Care

This is a highly adaptable and functional species for Piedmont clay. It thrives in full sun and average-to-dry soils, making it an excellent choice for Soil Stabilization on banks or as a Living Border along walkways. While many mints are known for aggressive spreading, P. tenuifolium is much better behaved, expanding slowly via short rhizomes to form a dense, weed-suppressing clump. To maintain a tidy shape, it can be cut back to the ground in late winter. It is exceptionally deer resistant due to the high essential oil content in its foliage, which emits a pleasant minty fragrance when brushed against.

Photo: "Pycnanthemum cf. tenuifolium" by peganum is licensed under CC BY-SA 2.0.

Photo: "Pycnanthemum tenuifolium (narrow-leaved mountain-mint), Warwick, RI" by Doug McGrady is licensed under CC BY 2.0.