2025 Perennial Plant of the Year

8/1/2024 7:56 pm

ANNOUNCING THE 2025

PERENNIAL PLANT OF THE YEAR®

(Chosen by the Perennial Plant Association and all information from their report)

Pycnathemum muticum

(Clustered Mountainmint)

Photography Credit: Chicago Botanic Garden

Clustered mountainmint (also known as blunt mountainmint or short-toothed mountainmint) is a tough and adaptable perennial native to meadows and open woodlands across much of the eastern United States west to Texas. It is not a true mint (Mentha spp.) but belongs to the same family and has similarly scented leaves. A must-have for pollinator gardens, heads of tiny white to light pink blooms attract butterflies, wasps, and bees from July to September. The inconspicuous flowers are upstaged by surrounding silver bracts, which give the illusion of frost in summer and persist for months. Clustered mountainmint has no serious disease issues, and its aromatic foliage is unpalatable to deer and rabbits.

Branched, vertical stems grow two to three feet tall and form a dense, weed-suppressing clump. Clustered mountainmint spreads by underground rhizomes and can be aggressive in moist conditions, though it is not invasive to the degree of true mints.

Site clustered mountainmint in an area where it can freely naturalize and mingle among other plants. Its silver sheen plays well with other flower colors and contrasts wonderfully with dark foliage. Companions include black-eyed Susans (Rudbeckia spp.), bee balms (Monarda spp.), blazing stars (Liatris spp.), Joe Pye weeds (Eutrochium spp.), and native grasses such as little bluestem (Schizachyrium scoparium) and switchgrass (Panicum virgatum).

Photography Credit: Chicago Botanic Garden

PLANT DATA

Hardiness
USDA Zones 4 to 8
Canadian Hardiness Zones 3 to 7
AHS Heat Zones 4 to 10

Light
Full sun to part shade

Size
24-36 inches (60-100 cm) tall; spreads widely by rhizomes

Origin
Eastern United States, west to Texas

Soil
Prefers medium to high moisture, fertile, well-draining soils. Tolerates clay soils. Less tolerant of drought than most other mountainmints.

Maintenance
Clustered mountainmint can spread aggressively, especially in wet soils. Rhizomes are easy to control by cutting them to the desired size with a spade and pulling the shoots by hand in spring. Seed heads may be left until early spring for winter interest. Tolerates heat and drought once established. No serious pest or disease issues.

Grower Notes

Pycnanthemum muticum is as easy in production as it is in the landscape.

Pot in fall to bulk/overwinter for early spring sales.
Pot in early spring for late spring/early summer sales (does not require vernalization).
Finishing schedule for 1 gal: 4 to 6 weeks from a 32 cell liner; 6 to 9 weeks from a 50 or a 72.
Shear in spring (repeatedly, if necessary).

9/28/2022 4:00 pm

ANNOUNCING THE 2023

PERENNIAL PLANT OF THE YEAR®:

Rudbeckia 'American Gold Rush' PP28498

Black-eyed Susan

Photography Credit: Intrinsic Perennial Gardens

8/12/2022 5:26 pm

Read about Eric Mack's creation of The Kai Garden, a story about an extraordinary young man finding his way out of grief by gardening. He now grows exciting new, rare and unusual perennials at his Atlanta home which he retails via pop-up sales.

1/17/2022 10:09 am

The horticulture world lost a grant plantsman and advocate for native azaleas, Ernest Koone, owner of Lazy K Nursery in Pine Mountain, Georgia on January 6, 2022. Ernest was always generous with Georgia Perennial Plant Association, giving both time and resources to us. We will miss him.