common evening primrose (Oenothera biennis)
common evening primrose
Oenothera biennis L. ssp. caeciarum Munz
Oenothera biennis L. ssp. centralis Munz
Oenothera biennis L. var. pycnocarpa (Atk. & Bartlett) Wiegand
Oenothera muricata L.
Oenothera pycnocarpa Atk. & Bartlet
CONFIRMATION STATUS: Pending confirmation.
TAXONOMY: The currently accepted scientific name for common
evening primrose is Oenothera biennis L.
NATIVE STATUS: Native, United States and Canada.
GENERAL BOTANICAL CHARACTERISTICS:
Habit: This native biennial plant can be 8' tall, although it is often shorter.
There is usually a central stem with alternate leaves, but sometimes there
will be multiple stems in open areas, creating a bushy appearance. The
stems are light green or red, and are covered with white hairs.
Leaves: The light or olive green leaves are up to 8" long and 2" wide, but
usually smaller. They are lanceolate and resemble willow leaves. The mar-
gins of the leaves are smooth or slightly dentate, and are nearly hairless.
Smaller secondary leaves often appear at the axils of major leaves on the
Flowers: A panicle of pale yellow flowers occurs at the apex of the plant
(or at the ends of major stems, if the plant is bushy). Each flower is about
1" across when fully open, with 4 petals and prominent stamens, and a
long green calyx. The flowers remain open from evening to early morning,
but will remain open longer on cloudy days. They have a mild lemony
scent, and bloom from mid-summer to fall on mature plants.
Fruit/Seeds: Long narrow seedpods develop, which split open from the
top to release many tiny, irregular brown seeds. They are small enough
to be dispersed by the wind, and can remain viable in the soil after 70
Roots: The root system consists of a fleshy taproot.
REGENERATION PROCESS: Common evening primrose propogates
itself by reseeding.
HABITAT TYPES: Common evening primrose is a common plant that
is particularly conspicuous during late summer or fall. Disturbed areas are
favored in both natural and developed habitats, including mesic to dry
black soil prairies, sand prairies, thickets, glades, lakeshore dunes, aban-
doned fields, roadsides and railroads, slopes of drainage ditches, vacant
SITE CHARACTERISTICS: The preference is full sun, average mois-
ture, and a soil that is somewhat sandy, but other growing conditions are
SEASONAL DEVELOPMENT: Common evening primrose blooms
from mid-summer to fall on mature plants.
GENERAL DISTRIBUTION: Common evening primrose occurs
throughout most of the United States (excepting Arizona and the central
Rocky Mountains states) and all of the southern provinces of Canada.
SKY MEADOWS DISTRIBUTION: To be determined.
IMPORTANCE AND USES: Moths pollinate the flowers, particularly
Sphinx moths. Other occasional visitors include the ruby-throated hum-
mingbird, honeybees, bumblebees, and Anthedonia compta (primrose
miner bee), the latter being an oligolege. These insects seek nectar, al-
though some of the bees collect pollen. The caterpillars of several moths
feed on the foliage. This includes Endryas unio (pearly wood nymph),
Desmia funeralis (grape leaffolder moth), Hyles lineata (white-lined
sphinx), and Mompha eloisella (momphid moth; bores through stems).
Various beetles feed on the foliage, including Popillia japonica (Japanese
beetle), Grahops pubescens (leaf beetle sp.), Altica fusconenea (flea
beetle sp.), and several Curculio beetles. The seeds are eaten by gold-
The mature seeds of common evening primrose contain approximately
7–10% gamma-linolenic acid, a rare essential fatty acid. The Oenothera
biennis seed oil is used to reduce the pains of premenstrual stress syn-
drome and is beneficial to the skin of the face. Also, poultices contain-
ing Common evening primrose were at one time used to ease bruises and
speed wound healing.
Its leaves are edible and traditionally were used as a leaf vegetable.
Crooked Run Valley