Heuchera americanaL.

American alumroot

WFO wfo-0001135392 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Heuchera americana, photographed by Jeff Clark
fig. a Jeff Clark, CC BY 4.0 / 2022-05-08 / obs. 196124136

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 24 botanical countries

Regions where Heuchera americana is native: Alabama, Arkansas, Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Ontario, Pennsylvania, South Carolina, Tennessee, Virginia, West Virginia AlabamaArkansasConnecticutGeorgiaIllinoisIndianaKentuckyLouisianaMarylandMichiganMississippiMissouriNew JerseyNew YorkNorth CarolinaOhioOklahomaOntarioPennsylvaniaSouth CarolinaTennesseeVirginiaWest Virginia Delaware
Native distribution of Heuchera americana, 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
Alabama ALA NORTHERN AMERICA
Arkansas ARK
Connecticut CNT
Delaware DEL
Georgia GEO
Illinois ILL
Indiana INI
Kentucky KTY
Louisiana LOU
Maryland MRY
Michigan MIC
Mississippi MSI
Missouri MSO
New Jersey NWJ
New York NWY
North Carolina NCA
Ohio OHI
Oklahoma OKL
Ontario ONT
Pennsylvania PEN
South Carolina SCA
Tennessee TEN
Virginia VRG
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.

Flowering 164 in flower of 349 examined

Proportion of examined Heuchera americana in flower, by month
Month In flower Examined Share 95% interval
Jan 0 6 0% 0% to 39%
Feb 0 5 0% 0% to 43%
Mar 3 28 11% 4% to 27%
Apr 34 81 42% 32% to 53%
May 79 114 69% 60% to 77%
Jun 45 65 69% 57% to 79%
Jul 3 13 23% 8% to 50%
Aug 0 5 0% 0% to 43%
Sep 0 13 0% 0% to 23%
Oct 0 9 0% 0% to 30%
Nov 0 4 too few examined
Dec 0 6 0% 0% to 39%

Peak flowering in May. Each bar is the share of Heuchera americana observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 164 of 349 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Where it actually grows measured, from 1,833 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -6.6 °C -2.4 °C 1.9 °C
Warmest month, mean daily high 26.7 °C 29.8 °C 32.7 °C
Annual rainfall 1,004 mm 1,212 mm 1,513 mm
Rainfall in the driest quarter 191 mm 252 mm 310 mm

It is found where winters bring hard 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 1,833 research-grade observations of Heuchera americana 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. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 26 synonyms

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.

  • Heuchera americana f. angustipetala Rosend., Butters & Lakela
  • Heuchera americana var. affinis Regel
  • Heuchera americana var. brevipetala Rosend., Butters & Lakela
  • Heuchera americana var. calycosa (Small) Rosend., Butters & Lakela
  • Heuchera americana var. foliosa Moric. ex Ser.
  • Heuchera americana var. glabriuscula Schult. ex Ser.
  • Heuchera americana var. gracilior Regel
  • Heuchera americana var. heteradenia Fernald
  • Heuchera americana var. interior Rosend., Butters & Lakela
  • Heuchera americana var. laxa Regel
  • Heuchera americana var. minima Regel
  • Heuchera americana var. robusta Regel
  • Heuchera americana var. subtruncata Fernald
  • Heuchera americana var. typica Rosend., Butters & Lakela
  • Heuchera calycosa Small
  • Heuchera cortusa Michx.
  • Heuchera curtisii Torr. & A.Gray ex A.Gray
  • Heuchera curtisii var. crenata Rydb.
  • Heuchera hirsuticaulis Rydb.
  • Heuchera hispida Pursh
  • Heuchera hispida var. hirsuticaulis Wheelock
  • Heuchera lancipetala Rydb.
  • Heuchera lucida Schlecht.
  • Heuchera portula Michx.

and 2 more.

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. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. 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.