Pycnanthemum torreyiBenth.

WFO wfo-0000289032 Accepted WFO 2026-06 4 photographs CC BY

Plate 1 figs. a–d · 1 observation

This species has been photographed under an open licence only 1 time, so some figures below are different views of the same plant, taken on the same day, rather than different individuals. They are usually different parts of it: the leaf, the flower, the bark.

Pycnanthemum torreyi, photographed by Bonnie Semmling
fig. a Bonnie Semmling, CC BY 4.0 / 2020-07-16 / obs. 84786854
Pycnanthemum torreyi, photographed by Bonnie Semmling
fig. b Bonnie Semmling, CC BY 4.0 / obs. 84827171
Pycnanthemum torreyi, photographed by Bonnie Semmling
fig. c Bonnie Semmling, CC BY 4.0 / obs. 84786921
Pycnanthemum torreyi, photographed by Bonnie Semmling
fig. d Bonnie Semmling, CC BY 4.0 / obs. 84827179

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 15 botanical countries

Regions where Pycnanthemum torreyi is native: Connecticut, Delaware, District of Columbia, Georgia, Illinois, Kansas, Maryland, Missouri, New Jersey, New York, North Carolina, Pennsylvania, South Carolina, Tennessee, West Virginia ConnecticutGeorgiaIllinoisKansasMarylandMissouriNew JerseyNew YorkNorth CarolinaPennsylvaniaSouth CarolinaTennesseeWest Virginia DelawareDistrict of Columbia
Native distribution of Pycnanthemum torreyi, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Connecticut CNT NORTHERN AMERICA
Delaware DEL
District of Columbia WDC
Georgia GEO
Illinois ILL
Kansas KAN
Maryland MRY
Missouri MSO
New Jersey NWJ
New York NWY
North Carolina NCA
Pennsylvania PEN
South Carolina SCA
Tennessee TEN
West Virginia WVA

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Where it actually grows measured, from 43 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -4.4 °C -2.1 °C 0.7 °C
Warmest month, mean daily high 28.8 °C 30.9 °C 31.2 °C
Annual rainfall 1,053 mm 1,149 mm 1,341 mm
Rainfall in the driest quarter 209 mm 234 mm 271 mm

It is found where winters bring light frost. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 43 research-grade observations of Pycnanthemum torreyi that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one.

Also published as 1 synonym

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Koellia torreyi (Benth.) Kuntze

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.