Evening Primrose Planting Techniques and Cultivation Management Points

Evening primrose (Oenothera biennis) is an erect biennial robust herbaceous plant of the genus Oenothera in the family Onagraceae, also known as evening star, sundrops, mountain sesame, wild sesame, etc. It is native to North America and was introduced to Europe early on, then spread rapidly through the world's temperate and subtropical regions. It is cultivated in Northeast China, North China, East China and Southwest China and has long since become naturalized. Let us take a look at evening primrose planting techniques below!

Evening Primrose Growing Environment

Evening primrose has strong adaptability, tolerates acid and drought, and has no strict requirements for soil. It can generally grow on neutral, slightly alkaline or slightly acidic, well-drained, loose soil. In soil that is too wet, the roots are prone to disease. In the north it is an annual plant, and south of the Huai River it is a biennial plant. It often grows on open barren slopes and roadsides, tolerates drought and poor soil, and is suitable for planting in black soil, sandy soil, loess, young forest land, mildly saline-alkali land, wasteland, riverbank land and hillside land.

Evening Primrose Seed Propagation

Evening primrose can be sown in both spring and autumn. The autumn sowing period is from mid-October until before the ground freezes. If there is heavy winter snow, autumn sowing is better than spring sowing; if there is little winter snow, it easily causes missing seedlings and broken rows. Spring sowing can be done before wheat sowing, when the soil has thawed 2-3 cm. Because the seeding rate is low, use 60 kg of diammonium phosphate per hectare as a filler mixed with the seed; if insufficient, a certain amount of dry sawdust or fried wheat, rapeseed, etc. can be added for sowing. Sow at a depth of 1-2 cm and press the soil promptly after sowing. The seed rate is 6 kg per hectare, with 400,000-500,000 plants retained per hectare. The sowing density must not be too low, otherwise branching occurs and the maturity period becomes uneven.

Evening Primrose Cutting Techniques

1. Cuttings: The branches used for evening primrose cuttings are called cuttings. Usually combined with pinching work, the thick, pest- and disease-free top shoots that are removed are used as cuttings. The optimum temperature for rooting of cuttings is 18-25°C. Below 18°C, cuttings root with difficulty and slowly; above 25°C, the cut surface of the cutting is easily infected by pathogens and rots, and the higher the temperature, the greater the proportion of rot.

2. Temperature management: When low temperatures are encountered after cutting, the main measure for keeping warm is to wrap the flowerpot or container used for cuttings with plastic film. When the temperature is too high after cutting, the main cooling measure is to shade the cuttings, blocking 50-80% of sunlight, while misting the cuttings 3-5 times a day. On sunny days with higher temperatures, mist more often; on cloudy and rainy days with lower temperatures and higher humidity, mist less often or not at all.

3. Humidity management: After cutting, the relative humidity of the air must be maintained at 75-85%. Humidity can be increased by misting the cuttings 1-3 times a day. On sunny days, the higher the temperature, the more often you mist; on cloudy and rainy days, the lower the temperature, the less often you mist or do not mist at all. However, excessive misting makes cuttings susceptible to pathogen infection and rot, because many kinds of pathogens exist in water.

4. Light management: Cutting propagation cannot do without sunlight, but the stronger the light, the higher the temperature inside the cuttings, the more vigorous the transpiration of the cuttings, and the more water consumed, which is not conducive to the survival of the cuttings. Therefore, after cutting, 50-80% of sunlight must be blocked. After the root system grows out, gradually remove the shade net. On sunny days, remove the shade net at 4:00 p.m. each day and cover it again before 9:00 a.m. the next day.

Evening Primrose Planting Techniques

1. Site selection and land preparation: Evening primrose is robust by nature, tolerates cold, drought and poor soil, likes light, and avoids waterlogging. Choose fertile soil with good drainage and previous crops of beans or melons. Continuous cropping is possible, but land with residues of herbicides such as chlorsulfuron, thifensulfuron-methyl, pursuit (imazethapyr) or clomazone must not be planted with evening primrose. For land preparation, bean stubble and mixed stubble can be directly harrowed and ridged in autumn.

2. Potting substrate: The substrate used for potting can be one of the following: vegetable garden soil + cinder = 3 parts + 1 part, or garden soil + medium-coarse river sand + sawdust (mushroom residue) = 4 parts + 1 part + 2 parts, or peat + perlite + ceramsite = 2 parts + 2 parts + 1 part, or vegetable garden soil + cinder = 3 parts + 1 part, or peat + cinder + ceramsite = 2 parts + 2 parts + 1 part, or sawdust + vermiculite + medium-coarse river sand = 2 parts + 2 parts + 1 part.

3. Potting seedlings: When potting seedlings, first place coarse-grained substrate or ceramsite 2-3 cm thick at the bottom of the pot as a drainage layer, sprinkle a layer of fully decomposed organic fertilizer on top as base fertilizer about 1-2 cm thick, then cover with a layer of substrate about 1-2 cm thick, and then place the plant in, so as to separate the fertilizer from the root system and avoid burning the roots. After potting, water thoroughly once and keep in a slightly shaded environment for one week.

4. Transplanting seedlings: When transplanting seedlings, first dig the planting hole, sprinkle a layer of organic fertilizer at the bottom of the planting hole as base fertilizer about 4-6 cm thick, then cover with a layer of soil and place the seedling in, so as to separate the fertilizer from the root system and avoid burning the roots. After placing the seedling in, backfill the soil to cover the root system, press the soil firm with your foot, and water thoroughly once.

5. Field management: Before the second pair of true leaves expands, the seedlings are very similar to weed seedlings and easily confused, so hoeing and weeding cannot be done at this time; it can only be done after the second pair of true leaves has unfolded. When the seedlings grow to 5-6 leaves and there are many grass weeds, clethodim or fluazifop-P-butyl can be sprayed to kill the weeds. During the growth period, 2 rounds of hoeing and 2 cultivations should be carried out. The hoeing and ridging must be finished before flowering. When the seedlings cover the ridges, carry out the first round of hoeing and cultivation. In late July and early August, carry out 2 rounds of manual pulling of large weeds so that there are no weeds in the field taller than the evening primrose plants.

6. Harvesting and processing: Evening primrose has an indeterminate inflorescence, and the fruits mature successively. Generally, when 3-4 bottom pods turn yellow and are about to split, it is the best harvest period, specifically in mid-to-late September; if later, the early-maturing fruits will have dried and split and the seeds will scatter on their own. It can be cut and sun-dried manually or with a swather. After drying for 5-7 days, use a combine harvester to pick up the grain or thresh manually. After harvest, the seeds are graded and cleaned with a grain cleaning machine to remove impurities. After drying until the moisture content drops below 11%, bag them for storage or sale.

Cultivation Points for Showy Evening Primrose

Showy evening primrose (Oenothera speciosa) grows relatively quickly and can also suppress weed growth. Artificially planting showy evening primrose is not very difficult. Because the appearance of showy evening primrose is very beautiful, it is now loved by more and more flower enthusiasts. So how can you grow showy evening primrose well?

Showy Evening Primrose

Showy evening primrose has strong adaptability and no strict requirements for soil. It tolerates cold, drought and poor soil, likes light, and avoids waterlogging. Bolting and flowering require a certain low-temperature stimulus.

Showy evening primrose performs best when cultivated in courtyards in ventilated, open places in loose, fertile, well-drained sandy loam soil. It can also be potted and placed on a balcony for viewing. Under the moonlight in the quiet night, waves of delicate fragrance make one feel refreshed. Showy evening primrose has strong self-seeding ability. After one planting, its self-sown seedlings can grow on their own every year and bloom continuously.

Showy evening primrose has no strict requirements for water and fertilizer. Generally, sufficient organic fertilizer and humus are applied before planting, and topdressing is usually not needed during the growth period. It is relatively sensitive to nitrogen fertilizer and tends to grow excessive branches and leaves. If water and fertilizer are too abundant or management is neglected for a long time, it is prone to excessive growth and lodging and reduced flower quantity. Generally, apply liquid fertilizer once before full bloom, which can improve the flowering effect and promote full seeds.

Water appropriately in summer. Usually, in years with abundant rainfall, no irrigation is needed; in dry years, irrigate appropriately 1-2 times. Before winter, irrigate with antifreeze water, which can improve drought resistance, cold resistance and overwintering ability. In early spring, water thoroughly with green-up water, which can promote early sprouting. In the later cultivation period, pay attention to controlling water and fertilizer to control excessive growth and maintain a good landscape effect.

Cultivation Techniques for the Economic Plant Evening Primrose