Oenothera fruticosaL.

Shrubby sundropsnarrowleaf evening primrose

WFO wfo-0001087414 Accepted WFO 2026-06 8 photographs CC0 / CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Oenothera fruticosa, photographed by Michael J. Papay
fig. a Michael J. Papay, CC BY 4.0 / 2022-05-31 / obs. 202229841

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.

The specimen a real sheet, in a real collection

Herbarium
The New York Botanical Garden
Accession
233540
Filed as
Oenothera fruticosa f. diversifolia H.Lév.
Det. by
G. B. Straley 1976-01-01
Collected
F. S. Earle 1897
Origin
US
The sheet
View the digitised specimen (CC BY 4.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 25 botanical countries

Regions where Oenothera fruticosa is native: Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maryland, Massachusetts, Mississippi, Missouri, New Jersey, New York, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Virginia, West Virginia AlabamaArkansasConnecticutFloridaGeorgiaIllinoisIndianaKentuckyLouisianaMarylandMassachusettsMississippiMissouriNew JerseyNew YorkNorth CarolinaOhioOklahomaPennsylvaniaSouth CarolinaTennesseeVirginiaWest Virginia DelawareDistrict of Columbia
Native distribution of Oenothera fruticosa, 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
District of Columbia WDC
Florida FLA
Georgia GEO
Illinois ILL
Indiana INI
Kentucky KTY
Louisiana LOU
Maryland MRY
Massachusetts MAS
Mississippi MSI
Missouri MSO
New Jersey NWJ
New York NWY
North Carolina NCA
Ohio OHI
Oklahoma OKL
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 349 in flower of 368 examined

Proportion of examined Oenothera fruticosa in flower, by month
Month In flower Examined Share 95% interval
Jan 0 0 too few examined
Feb 0 0 too few examined
Mar 1 2 too few examined
Apr 29 31 94% 79% to 98%
May 171 175 98% 94% to 99%
Jun 110 116 95% 89% to 98%
Jul 29 30 97% 83% to 99%
Aug 7 9 78% 45% to 94%
Sep 0 2 too few examined
Oct 2 3 too few examined
Nov 0 0 too few examined
Dec 0 0 too few examined

Peak flowering in May. Each bar is the share of Oenothera fruticosa 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. 349 of 368 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 7 months have fewer than 5 examined observations, so no proportion is drawn for them. 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 1,434 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -3.6 °C 0.8 °C 3.7 °C
Warmest month, mean daily high 28.6 °C 31.3 °C 33.0 °C
Annual rainfall 1,049 mm 1,210 mm 1,488 mm
Rainfall in the driest quarter 215 mm 259 mm 312 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 1,434 research-grade observations of Oenothera fruticosa 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 55 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.

  • Kneiffia allenii Small
  • Kneiffia angustifolia Spach
  • Kneiffia arenicola Small
  • Kneiffia brevistipata Pennell
  • Kneiffia floribunda Spach
  • Kneiffia fruticosa (L.) Spach ex Raim.
  • Kneiffia fruticosa var. differta Millsp.
  • Kneiffia fruticosa var. humifusa Pennell
  • Kneiffia fruticosa var. unguiculata (Fem.) Moldenke
  • Kneiffia linearis Spach
  • Kneiffia linearis var. allenii Britton
  • Kneiffia longipedicellata Small
  • Kneiffia maculata Spach
  • Kneiffia riparia Walp.
  • Kneiffia semiglandulosa Pennell
  • Kneiffia subglobosa Small
  • Kneiffia suffruticosa Spach
  • Kneiffia tetragona var. longistipata Pennell
  • Kneiffia velutina Pennell
  • Oenothera arenicola (Small) Coker
  • Oenothera florida Salisb.
  • Oenothera frutescens hort. ex Jacques
  • Oenothera fruticosa f. angustifolia H.Lév.
  • Oenothera fruticosa f. diversifolia H.Lév.

and 31 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.