Oenothera biennis - L.
Common Name Evening Primrose, Sun Drop, Common evening primrose
Family Onagraceae
USDA hardiness 4-8
Known Hazards Lowers the threshold for epileptic fits (avoid). Caution if on anticoagulants. Combining with phenothiazines (allopathic medication) can trigger seizures. Adverse effects: may cause headaches and nausea on an empty stomach. Diarrhoea with high doses. Seizures in schizophrenic patients on phenothiazines (allergy antihistamines) [301].
Habitats Dunes, roadsides, railway banks and waste places in Britain[17], often in sandy soils[4].
Range Eastern N. America - Labrador, south to Florida and Texas. Naturalized in Britain.
Edibility Rating  
Other Uses  
Weed Potential Yes
Medicinal Rating  
Fully Hardy Well drained soil Moist Soil Full sun

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Oenothera biennis Evening Primrose, Sun Drop, Common evening primrose

Oenothera biennis Evening Primrose, Sun Drop, Common evening primrose
Physical Characteristics
 icon of manicon of flower
Oenothera biennis is a BIENNIAL growing to 1.2 m (4ft).
It is hardy to zone (UK) 4 and is not frost tender. It is in flower from Jun to September, and the seeds ripen from Aug to October. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Lepidoptera, bees, self.The plant is self-fertile.
It is noted for attracting wildlife.
Suitable for: light (sandy) and medium (loamy) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.

Onagra biennis. Brunyera biennis. Oenothera muricata. Onagra muricata.

 Meadow; Cultivated Beds;
Edible Uses
Edible Parts: Flowers;  Leaves;  Oil;  Root;  Seedpod.
Edible Uses: Oil.

Root - cooked. Boiled and eaten like salsify[4, 12, 27, 33, 66]. Fleshy, sweet and succulent[74]. Wholesome and nutritious[2]. A peppery taste[159]. The taste somewhat resembles salsify or parsnips[183]. Young shoots - raw or cooked[2, 12, 52, 85, 183]. Mucilaginous, with a peppery flavour, they are best used sparingly[159]. Another source suggests that the shoots should not be eaten[9]. Flowers - sweet. Used in salads or as a garnish[183]. Young seedpods - cooked. Steamed[183]. The seed contains 28% of a drying oil[114]. It is edible and a very good source of gamma-linolenic acid[141], an essential fatty acid that is not found in many plant sources and has numerous vital functions in the body. The seed, however, is very small and difficult to harvest, it has to be done by hand[160]. Overall yields are low, making the oil very expensive to produce.
Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Anticholesterolemic;  Antipruritic;  Astringent;  Hypotensive;  Miscellany;  Sedative.

The bark and the leaves are astringent and sedative[4, 21]. They have proved of use in the treatment of gastro-intestinal disorders of a functional origin, whooping cough and asthma[4]. A syrup made from the flowers is also an effective treatment for whooping cough[7]. The bark is stripped from the flowering stem and dried for later use, the leaves are also harvested and dried at this time[4]. Evening primrose oil has become a well-known food supplement since the 1980's. Research suggests that the oil is potentially very valuable in the treatment of multiple sclerosis, pre-menstrual tension, hyperactivity etc[66]. It is also taken internally in the treatment of eczema, acne, brittle nails, rheumatoid arthritis and alcohol-related liver damage[238]. Regular consumption of the oil helps to reduce blood cholesterol levels and lower the blood pressure[21, 66]. The seed is a good source of gamma-linolenic acid, an unsaturated fatty acid which assists the production of hormone-like substances[222, 238]. This process is commonly blocked in the body, causing disorders that affect the uterine muscles, nervous system and metabolism[238]. The poulticed root is applied to piles and bruises[222]. A tea made from the roots is used in the treatment of obesity and bowel pains[222].


Other Uses
Cosmetic;  Dye;  Miscellany;  Oil.

The oil from the seed is added to skin preparations and cosmetics. It is often combined with vitamin E to prevent oxidation[238]. A yellow dye is obtained from the flowers[7]. A finely ground powder made from the flowering stems is used cosmetically in face-masks to counteract reddened skins[7].
Cultivation details
Prefers a dryish well-drained sandy loam and a warm sunny position[1, 4, 200], though it is tolerant of most soils[4]. Heavy clay soils may induce winter rots[200]. Grows well on very poor soils[160, 238]. Established plants are drought resistant[160]. Formerly cultivated for its edible roots, the evening primrose is being increasingly cultivated for the oil contained in its seed which contains certain essential fatty acids and is a very valuable addition to the diet[66]. See the notes on medicinal uses for more details. The flowers open in the evening and are strongly scented with a delicious sweet perfume[245], attracting pollinating moths[4]. The seeds are a good food source for birds[200]. Plants usually self-sow freely if they are growing in a suitable position, they can naturalize in the wild garden[4, K].
Seed - sow in situ from late spring to early summer[200].
Other Names
Found In
Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

Conservation Status
IUCN Red List of Threatened Plants Status :
Related Plants
Latin NameCommon NameEdibility RatingMedicinal Rating
Clarkia bilobaTwolobe clarkia, Mariposa clarkia, Brandegee's clarkia11
Clarkia purpureaWinecup clarkia10
Jussieva repens 01
Oenothera albicaulisWhitest Evening Primrose21
Oenothera brevipesGolden Suncup20
Oenothera elata hookeriHooker's Evening Primrose21
Oenothera glaziovianaLarge-Flower Evening Primrose, Redsepal evening primrose22
Oenothera lamarckiana 10
Oenothera odorata 10


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Botanical References
Links / References
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Readers comment
Emile Chabrouillaud   Wed Jun 8 05:01:36 2005
I have one growing in my front yard flower bed Or I should say twelve stalks. Each stalk is blooming at a different pace. This plant is located in Visalia, California. It started with a package of wild flower seeds. They are up to 5 feet and plus tall and has yellow flowers.
   Mon Jan 8 2007

Biothemen Informations on Oenothera in German language

Fons smits   Thu Jun 14 2007
I have several appearing in my garden this year in Zionsville, Indiana. These just started growing, didn't do anything. The flowers are beautiful yellow and open at 8-9 pm and are finished blooming around noon next day.
Ian   Mon Oct 20 2008

Evening Primrose oil is an effective herbal remedy to treat eczema and skin conditions Evening Primrose oil has long been used as a herbal remedy that can treat and heal a wide range of skin conditions. Evening Primrose oil is also very effective in treating menstrual discomfort, acne and even rosacea.

Gionni Benacchio   Wed Dec 17 2008
I`ve founded Evening Primrose oil in Latvia as a sedative, each capsule contents 500mg. Can I add to this oil 5mg melatonin whithout any side-effect? Thanks. Gionni, Stockholm, Sweden
Heather   Fri Jun 12 2009
I have one of these in East TN. It is beautiful and in shade most of the day and is doing wonderfully! On cloudy days especially, the blooms stay most of the day. BEAUTIFUL!
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Subject : Oenothera biennis  

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