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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    (3 of 5)
Other Uses    (3 of 5)
Weed Potential Yes
Medicinal Rating    (5 of 5)
Care (info)
Fully Hardy Well drained soil Moist Soil Full sun
Oenothera biennis Evening Primrose, Sun Drop, Common evening primrose

Oenothera biennis Evening Primrose, Sun Drop, Common evening primrose


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Physical Characteristics

 icon of manicon of flower
Oenothera biennis is a BIENNIAL growing to 1.2 m (4ft).
See above for USDA hardiness. It is hardy to UK zone 4 and is not frost tender. It is in flower from June to September, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs) and is pollinated by Lepidoptera (Moths & Butterflies), bees. 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: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.

UK Hardiness Map US Hardiness Map


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

Plant Habitats

 Meadow; Cultivated Beds;

Edible Uses

Edible Parts: Flowers  Leaves  Oil  Root  Seedpod  Shoots
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.

References   More on Edible Uses

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  Eczema  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].

References   More on Medicinal Uses

The Bookshop: Edible Plant Books

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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].

Special Uses

Attracts Wildlife  Dynamic accumulator  Food Forest  Scented Plants

References   More on Other Uses

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]. In garden design, as well as the above-ground architecture of a plant, root structure considerations help in choosing plants that work together for their optimal soil requirements including nutrients and water. The root pattern is fleshy. Thick or swollen - fibrous or tap root [2-1].

References   Carbon Farming Information and Carbon Sequestration Information

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Plant Propagation

Seed - sow in situ from late spring to early summer[200].

Other Names

If available other names are mentioned here

Native Plant Search

Search over 900 plants ideal for food forests and permaculture gardens. Filter to search native plants to your area. The plants selected are the plants in our book 'Plants For Your Food Forest: 500 Plants for Temperate Food Forests and Permaculture Gardens, as well as plants chosen for our forthcoming related books for Tropical/Hot Wet Climates and Mediterranean/Hot Dry Climates. Native Plant Search

Found In

Countries where the plant has been found are listed here if the information is available

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 :

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Growth: S = slow M = medium F = fast. Soil: L = light (sandy) M = medium H = heavy (clay). pH: A = acid N = neutral B = basic (alkaline). Shade: F = full shade S = semi-shade N = no shade. Moisture: D = dry M = Moist We = wet Wa = water.


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Botanical 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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