Preface. Willow-leaved verbena, belonging to the verbena family, is a perennial herbaceous plant. It is also known as dragon sprout grass, iron horsewhip, or wind-necked grass.
This plant is slightly cold and has a bitter taste. It is often used in Chinese herbal medicine, mainly using the clean aerial parts of plants, which has the effects of clearing heat and detoxifying, invigorating blood and dissipating stasis, diuresis and swelling. Its roots can also be red, white diarrhea and other diseases.
Although the willow-leaved verbena is native to tropical America, it is now also a species included in the National Pharmacopoeia.
1. Plant characteristics of willow-leaved verbena.
1. Morphological characteristics.
Verbena willow has a plant height between 60 and 150 cm and is usually multi-branched.
The stems are square, the leaves are opposite, and the shape is oval to rectangular or oblong-lanceolate; The basal leaves are often coarsely serrated and notched, usually in three parts, the edges of the lobes are irregularly serrate, and there are coarse hairs on both sides of the leaves.
The inflorescence is spike-shaped, apical or axillary, slender like a whip; The flowers are small, and the corolla is lilac or blue. The fruit is capsule-shaped and about 02 cm, the exocarp is thin, dehiscates when ripe, and contains 4 small nuts.
2. Biological characteristics.
Verbena willow can be harvested for many years in a single plant in warm areas, but when planted in cold regions, the roots cannot overwinter due to the low temperature of winter, so they can only survive the cold season.
The flowers usually bloom from early July to late August, and the flowers gradually open from the lower end of the inflorescence upwards, and the fruit ripens from mid-August to October, and the growing season is about 165 days per year.
The seeds of verbena willow are triangular or rectangular in shape, almost equal in width at both ends, and about 015 to 020 cm, width about 005 to 008 cm, rough surface, earthy yellow or brownish yellow, dull, 1000-grain weight of about 038 grams and a lifespan of 1 year.
The suitable germination temperature is 20 to 30 degrees Celsius, of which 25 degrees Celsius germinates faster, and the germination rate can be as high as 90%.
Verbena willow-leaved is fertiliser-loving, prefers a humid environment but is not waterlogg-tolerant, and is sensitive to drought.
Generally, the soil can grow, but the soil layer is deep, fertile loam and sandy loam soil is more robust, and low-lying and flood-prone areas are not suitable for planting willow-leaved verbena.
3. Reproduction methods.
Verbena willow can be propagated by sowing, cuttings and root cuttings. At the time of sowing, the suitable germination temperature is 20-25 degrees Celsius, and spring is the best time to sow seeds, so as to prolong the flowering and viewing time.
Although the sowing method can obtain more plants in a shorter period of time, it takes a longer time from sowing to flowering.
Cuttings propagation is also an ideal way to propagate, which is generally carried out in spring and summer, and the top bud cuttings are appropriate. After cuttings, willow-leaved verbena takes root easily, and seedlings can be formed in about 4 weeks.
The root cutting method is mainly suitable for the dormant mother plant in autumn, and it can be cut and replanted in the spring, which can promote the growth and reproduction of the plant.
2. Cultivation and management of willow-leaved verbena.
1. Seedling. Seedlings are mainly raised by sowing and propagation, and the suitable germination temperature is 20-25 degrees Celsius. Germination usually occurs within 10 to 15 days after sowing, and the whole seedling cycle is 40 to 45 days, so it is best to choose January to May for sowing.
Generally, 200 hole trays are selected for seedling raising, which is conducive to subsequent transplanting and planting. In terms of medium, peaty soil is often used because it ensures that the seedlings grow neatly and quickly.
2. Preparation before transplanting.
In the preparation of the land and soil, it is necessary to level the ground in the greenhouse and divide it into 4 furrows.
Next, relatively fertile arable land is selected and diammonium phosphate and carbendazim are sprinkled into the soil in proportion. Subsequently, the materials are thoroughly mixed with the soil by a rotary tiller, and then the soil is transferred to the greenhouse.
Because the seedlings transported over long distances may be infected by viruses during transportation, or spread the virus from other places to the local area, it is necessary to disinfect and sterilize the seedlings.
Mix carbendazim and yellow sand in a ratio of 1:5 and sprinkle it under the seedlings. After all the seedlings are placed, they also need to be disinfected and sterilized to ensure the health of the seedlings.
3. Transplanting. At 45 days after sowing, when the true leaves of willow-leaved verbena have reached 2 to 3 pairs and the root system has formed a clump, transplanting can be carried out.
It is recommended not to transplant the seedlings directly into the ground, as this will lead to slow initial growth and high mortality.
Generally, the seedlings are transplanted into a nutrient bowl with a size of 12 cm and 13 cm and grown for more than 1 month, and then planted to the actual planting site, which has the best effect.
During the transplanting process, if the number of transplanted seedlings is large, it may take several days to complete the transplanting work. During this time, it is necessary to sprinkle the seedlings in time to ensure that the seedlings do not wilt.
Before transplanting, the top of the verbena can be trimmed, leaving 2 or 3 pairs of true leaves, which can promote the branching of the willow-leaved verbena and avoid the plant growing too tall and affecting the ornamental effect.
When transplanting, sandy loam soil can be packed into a 12cm 13cm nutrient bowl, and willow-leaved verbena can be transplanted into the bowl.
When transplanting, it is important to bury the roots completely in the soil and keep them perpendicular to the ground to prevent the seedlings from being washed out or leaving part of the root system exposed during watering.
After transplanting is completed, the seedlings should be watered with a watering can in time to prevent dehydration. Before planting in the green area, it is necessary to irrigate several times to ensure the normal growth of the seedlings.
It is also important to control the temperature, it is best to control the temperature at 20 to 30 degrees Celsius, where 25 degrees Celsius is faster.
When the weather is fine, the cotton curtain of the greenhouse can be pulled up at 11:00 in the morning to allow the sun to fully illuminate the seedlings. In the evening, the cotton curtain should be lowered to maintain the temperature in the greenhouse.
Before and after transplanting, weeds in the nutrient bowl need to be removed to prevent the invasion of foreign weeds. Due to the small size of the seedlings, no chemical herbicides can be used.
If the temperature in the greenhouse is too high and the drainage is poor, it is easy to lead to the occurrence of root rot. At the beginning of the disease, you can spray 50% antibacterial special 1000 times liquid, spray once every 15 days, spray 3 4 times continuously.
4. Ventilation. If the greenhouse is not ventilated before planting, it will be difficult for willow-leaved verbena to adapt to the harsh environment and be vulnerable to external aggression.
However, if the greenhouse film is lifted to the top of the greenhouse at one time during ventilation, the temperature difference between the inside and outside of the greenhouse will be too large, resulting in the seedlings can not adapt to the low temperature and will wilt and die.
In general, a step-by-step approach can be taken when raising seedlings for ventilation. Lift the lower part of the film 10 cm and keep it in this state for 24 hours.
Then remove the shed film to the middle part of the greenhouse, also keep it for 24 hours, and finally lift all the shed film. In this way, gradual ventilation can gradually adapt the seedlings to environmental changes and avoid damage caused by excessive temperature differences.
5. Colonization. After watering, weeding, manure, ploughing, and raking preparations are completed, planting can be carried out.
At the time of planting, the method of planting large and small ridges is adopted. First of all, the ditch is made along the furrow at a distance of 5 cm from the edge of the furrow, and the spacing of the large ridge mulching is usually 25 30 cm, the depth of the furrow is 15 20 cm, and the spacing of the small ridge is 40 cm.
The spacing of the plants in the row should be kept at about 10 cm, usually about 10 plants per square meter, which is conducive to providing the required space for the branching and growth of the plants.
If planted too densely, it may lead to poor ventilation during later growth.
3. Field management of willow-leaved verbena.
1. Watering and fertilizing.
After planting, make sure to water thoroughly to keep the soil moist at a distance of 20 cm from the surface.
15~2.It begins to enter the early stage of full flowering within 5 months, and the full flowering period lasts for 25~3.0 months. During this process, the stems and leaves of the willow-leaved verbena will gradually turn willow-leafed.
Verbena is a drought-tolerant flower variety, so keep the soil moist but not too moist during the conservation process.
Due to the application of diammonium phosphate to the soil in the pan prior to transplanting and the application of cow manure prior to planting, refertilization is usually not required at a later stage. If the growth is not vigorous in the later stage, urea can be properly supplemented.
2. Weeding. Weeding is one of the routine tasks in field management, and it is also one of the effective measures to ensure the ornamental effect of plants. Timely weeding can prevent the growth of weeds and keep the planting area clean and beautiful.
It is necessary to "remove the weeds when they see them", that is, once they find that weeds are growing, they will be weed immediately to ensure that there are no weeds in the field. This can effectively reduce the competition of weeds for plant growth, and improve the growth rate and ornamental effect of plants.
3. Loosen the soil. If you choose to plant without mulching, you need to pay special attention to field drainage during the rainy season.
After the rain, the soil should be loosened in time to prevent the topsoil from compaction and affect the growth of the plants. By loosening the soil, the permeability of the soil can be increased, the accumulation of water can be reduced, which is conducive to drainage and soil compaction can be avoided.
In addition, loosening soil can also effectively reduce the occurrence of diseases, because loosening soil can promote the activity of microorganisms in the soil, enhance the respirability and aeration of the soil, thereby reducing the survival and reproduction of pathogens.
Therefore, loosening soil can not only prevent soil compaction, but also reduce the occurrence of diseases, so as to achieve twice the result with half the effort.
4. Overwintering management of willow-leaved verbena.
Verbena willow is a long-day thermophilic flower, its suitable growth temperature is 20 30 degrees Celsius, it is not cold-tolerant, it will appear sluggish to grow below 10 degrees Celsius, and the roots cannot overwinter below 0 degrees Celsius.
Therefore, in order to reduce the cost of seedling raising and maintenance, and at the same time ensure that willow-leaved verbena can safely overwinter, many places actively explore and innovate, learn from the experience of other places, and explore advanced conservation methods.
One way to do this is to divide the shoots of the willow-leaved verbena and then treat its roots.
The roots of part of the willow-leaved verbena are directly covered with membrane, and the other part adopts the method of building an arch to improve the physical properties of the soil, increase the temperature and humidity of the soil, and promote the development of the root system, so that the roots of willow-leaved verbena are not damaged by frost.
Later, through comparison, it was found that the germination rate of willow-leaved verbena directly covered with film was only 30%, while the germination rate of arch shed was more than 98%.
These results indicate that the construction of arch canopies can more effectively protect the roots of Verbena willow and improve its success rate for wintering.
Epilogue. Due to the high temperature requirements of willow-leaved verbena, the roots are not allowed to freeze. Innovative maintenance methods, such as mulching and arching, have been used to increase the success rate of wintering.
This not only reduces costs, but also ensures the growth of the plants. In agricultural production, continuous exploration and innovation, combined with the characteristics of the local environment, is an effective way to improve crop yield and quality.
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3] Cultivation and management techniques of Verbena willow[J].JIN Wendong; Zhang Qing. Flower Bonsai (Flower Gardening), 2013(05).
4] Cultivation and management techniques of Verbena willow[J].JIN Wendong; Zhang Qing. Flower Bonsai (Flower Gardening), 2013
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