common evening primrose

(Oenothera biennis)

Conservation Status
common evening primrose
  IUCN Red List

not listed


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FACU - Facultative upland


FACU - Facultative upland

  Northcentral & Northeast

FACU - Facultative upland


Common evening primrose is an erect, biennial forb that rises usually on a single stem from a fleshy taproot. It can be up to 80 tall, though it is usually much shorter. In the first year it forms a rosette of basal leaves. In the second year it sends up a flowering stem. It dies after bearing fruit once.

The rosette leaves are green to pale green, stalked, narrowly inversely lance-shaped or lance-shaped, 4 to 12 long, and ¾ to 2 wide. The blade is broadly or narrowly angled at the tip and tapers gradually to the leaf stalk at the base. The upper and lower surfaces are covered with minute, straight, sharp, stiff, appressed hairs. The margin is toothed. The teeth are sometimes blunt, sometimes widely spaced. The lower part of the blade sometimes has broad, wavy teeth or is lobed.

The stem is erect, green, leafy, and sometimes flushed with red near the base. It may be unbranched or have a few branches rising from the rosette or a few branches on the main stem. It is densely to sparsely covered with minute, straight, sharp, stiff, appressed hairs, and also with longer, somewhat appressed to spreading hairs.

Stem leaves are alternate, narrowly inversely lance-shaped to lance-shaped or narrowly elliptic to elliptic, 2 to 8½ long, and to 2 wide. The blade is narrowly angled at the tip and wedge-shaped or tapered at the base. They are otherwise similar to rosette leaves. There is often a cluster of smaller, secondary leaves in the axil of the leaf.

The inflorescence is a stiff, relatively open spike of numerous flowers at the end of the stem and branches. The spike is unbranched but there is often a secondary spike below the main one. The central axis of the spike (rachis) sometimes red. It is densely to sparsely covered with minute, straight, sharp, stiff, appressed hairs, and also with longer, somewhat appressed to spreading hairs.

The individual flowers are stalkless. What appears to be a flower stalk is actually a structure formed by the fused bases of the sepals, petals, and stamens (hypanthium). The hypanthium is yellowish-green, sometimes flushed with red. It is sparsely to densely covered with short, straight, glandular hairs and also sparsely covered with long, soft, shaggy hairs. When in bud it is 1 to 19 16 long, 1 32to 116 in diameter, widely spreading near the rachis then strongly ascending, with the bud held upright. When in bloom the hypanthium elongates, straightens somewhat, and the flower is held at about a 45° angle.

The flowers are crowded and 1 to 2 in diameter when fully open. There are 4 sepals, 4 petals, 8 stamens, and 1 style. The sepals are yellowish-green, linear, ½ to long, and strongly bent backward along the hypanthium. The petals are yellow, rarely pale yellow, very broadly egg-shaped, ½ to 1 long, and 9 16 to 11 16 wide. They are broadly rounded and notched at the tip. They fade to orange as they begin to wither. The stamens extend only slightly beyond the corolla. They have 5 16 to long filaments and to ¼ long anthers. The style has a distinctive, 4-lobed, cross-shaped stigma. The flowers open around sunset and on cloudy days, and close by noon except on cloudy days, when they remain open. They change from closed to fully open in just one minute. They are pollinated by hawk moths or sphinx moths, which feed on their nectar at night. The hypanthium, petals, and sepals are deciduous, withering and falling off when the fruit is formed. The flowers have a mild lemony scent.

The fruit is a cylinder-shaped, ¾ to 19 16 long, to ¼ in diameter, 4-celled capsule. The capsule is green, stalkless; bluntly 4-angled with rounded angles; thickest at the base and tapered toward the tip; and straight, not curved near the base. Each cell of the capsule contains two rows of dark brown, egg-shaped seeds. The seeds do not have a tuft of hairs (pappus) at the top.




20 to 80


Flower Color




Similar Species


Cleland’s evening primrose (Oenothera clelandii) is a smaller plant, no more than 40 in height. The flowers are smaller and have diamond-shaped petals. The seed capsules are smaller and are curved.

Cut-leaved evening primrose (Oenothera laciniata) is a short plant, reaching only 18" at maturity. The leaves are lobed.

Northern evening primrose (Oenothera parviflora) has smaller flowers, no more than one inch wide.

Nuttall’s evening primrose (Oenothera nuttallii) has white flowers.

Perennial evening primrose (Oenothera perennis) is a shorter plant, reaching only 24 at maturity. It has smaller flowers, to ¾ wide.

Rhombic evening primrose (Oenothera rhombipetala) flower has diamond-shaped petals.

Toothed evening primrose (Oenothera serrulata) is a much shorter plant, reaching only 24 at maturity. It is usually found with clustered stems, which may be woody at the base. The leaves are toothed, and are linear or oblong and narrow.


Dry to moderate moisture. Prairies, fields, thickets, roadsides, railroads, disturbed sites and waste places. Full sun.




June to October


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 28, 29, 30.








Common and widespread

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Rosanae  
  Order Myrtales (myrtles, evening primroses, and allies)  


Onagraceae (evening primrose)  
  Subfamily Onagroideae  
  Tribe Onagreae  


Oenothera (evening primroses, sundrops, and beeblossoms)  
  Section Oenothera  
  Subsection Oenothera  

Subordinate Taxa






Oenothera biennis ssp. caeciarum

Oenothera biennis ssp. centralis

Oenothera biennis var. pycnocarpa

Oenothera muricata

Oenothera pycnocarpa


Common Names


common evening primrose

common evening-primrose

evening primrose



German rampion


hoary eveningprimrose

hog weed

king’s cure-all

weedy evening-primrose


The family name refers to the flowers which are partially to fully closed during the day, open in the evening, and close at noon. The plants are pollinated by hawk moths and sphinx moths, which feed on their nectar at night.













The upper angle where a branch, stem, leaf stalk, or vein diverges.



A collective name for all of the petals of a flower.



On plants: The thread-like stalk of a stamen which supports the anther. On Lepidoptera: One of a pair of long, thin, fleshy extensions extending from the thorax, and sometimes also from the abdomen, of a caterpillar.



A cup-like tubular structure of a flower formed from the fused bases of sepals, petals, and stamens, that surrounds the pistil. Its presence is diagnostic of many families, including Rose, Gooseberry, and Pea.



Long and narrow with parallel sides, as in a blade of grass.



The modified calyx composed of awns, scales, bristles, or feather-like hairs in plants of the Asteraceae family.



The main axis of a compound leaf, appearing as an extension of the leaf stalk; the main axis of an inflorescence.



The portion of the female part of the flower that is receptive to pollen.

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    common evening primrose   common evening primrose  


    common evening primrose   common evening primrose  


    common evening primrose   common evening primrose  


    common evening primrose      


    common evening primrose   common evening primrose  
    common evening primrose   common evening primrose  



  Oenothera biennis
Susanne Wiik
  Oenothera biennis  

Nattlys, Evening primrose

Frank Mayfield
  Oenothera biennis COMMON EVENING PRIMROSE  



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Other Videos
  Evening Primrose (Oenothera biennis) flower opening in real time

Uploaded on Jan 22, 2010

Back in early August 09' I saw for the first time the Evening Primrose flower open right in front of my eyes. I had no idea it happens so fast! How does it know when to open? I ran in to the house and grabbed my new camera and captured this video. My neighbor was over and we had a few drinks in us already as you will hear :-) The first 2 minutes are slow, then WOW! These plants are native to Minnesota.




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Avon Hills Forest SNA, North Unit

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