Cenothera biennis (LINN.)
Family: N.O. Onagraceae
Domtar Driveway, Cornwall, Ontario, Canada
August 2, 2010
Thanks to botanical.com.
Synonym: Tree Primrose.
Parts Used: Bark, leaves.
The Evening or Tree Primrose, though originally a native of North America, was imported first into Italy and has been carried all over Europe, being often naturalized on river-banks and other sandy places in Western Europe. It is often cultivated in English gardens, and is apparently fully naturalized in Lancashire and some other counties of England, having been first a garden escape.
The root is biennial, fusiform and fibrous, yellowish on the outside and white within. The first year, many obtuse leaves are produced, which spread flat on the ground. From among these in the second year, the more or less hairy stems arise and grow to a height of 3 or 4 feet. The later leaves are 3 to 5 inches long, 1 inch or more wide, pointed, with nearly entire margins and covered with short hairs. The flowers are produced all along the stalks, on axillary branches and in a terminating spike, often leafy at the base. The uppermost flowers come out first in June. The stalks keep continually advancing in height, and there is a constant succession of flowers till late in the autumn, making this one of the showiest of our hardy garden plants, if placed in large masses. The flowers are of a fine, yellow colour, large and delicately fragrant, and usually open between six and seven o’clock in the evening, hence the name of Evening Primrose. From a horticultural point of view, the variety grandiflora or Lamarkiana should always be preferred to the ordinary kind, as the flowers are larger and of a finer colour, having a fine effect in large masses, and being well suited for the wild garden.
The generic name is derived from oinos (wine) and thera (a hunt), and is an old Greek name given by Theophrastus to some plant, probably an Epilobium, the roots of which were eaten to provoke a relish for wine, as olives are now; others say it dispelled the effects of wine.
The large, bright yellow, fragrant flowers are mostly fertilized by twilight-flying insects, especially in the early season. Later the plants keep ‘open house’ practically all day. In America it is considered a troublesome pest; in England it is not formidable.
The roots of the Evening Primrose are eaten in some countries in the spring, and the French often use it for garnishing salads.
The Evening Primrose will thrive in almost any soil or situation, being perfectly hardy. It flourishes best in fairly good sandy soil and in a warm sunny position.
Sow the seeds an inch deep in a shady position out-doors in April, transplanting the seedlings when 1 inch high, 3 inches apart each way in sunny borders. Keep them free from weeds, and in September or the following March, transplant them again into the flowering positions. As the roots strike deep into the ground, care should be taken not to break them in removing.
Seeds may also be sown in cold frames in autumn for blooming the following year.
If the plants are once introduced and the seeds permitted to scatter, there will be a supply of plants without any special care.
Bark and leaves. The bark is peeled from the flower-stems and dried in the same manner as the leaves, which are collected in the second year, when the flowerstalk has made its appearance.
Medicinal Action and Uses:
Astringent and sedative. The drug extracted from this plant, though not in very general use, has been tested in various directions, and has been employed with success in the treatment of gastro-intestinal disorders of a functional origin, asthma and whooping cough.
It has proved of service in dyspepsia, torpor of the liver, and in certain female complaints, such as pelvic fullness.
The dose ranges from 5 to 30 grains.
Henslow mentions another species, Cenothera odorata, which he states is found wild in the south of England, but only as a garden escape. It grows to 2 feet in height, with purplish stems and yellow flowers, 3 to 4 inches across. They are sweet-smelling, hence its specific name.
In The Treasury of Botany a large whiteflowered species is also mentioned, said to have run wild over some parts of the Nilghiri Hills in India.
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