Willow leaf verbena is Verbenaceae Verbenaceae plants. Leaf blade cross opposite, the growth of the early leaves for the oval edge slightly notched, flower stem pumping high after the leaves turn into slender type such as willow leaf-like, leaf blade edge is still pointed is its main feature. The stem is square, and the whole plant is ciliated. The flowering period is from May to October, or even longer. The height of the plant is 100~150cm. terminal, small simple flowers are inserted on the top of the flower stem, purplish red or lavender.
Two: growth habit
Willow leaf vervain grassland is produced in South America (Brazil, Argentina and other places). Prefer sunny environment. Not cold, afraid of rain _. Sex like warm climate, the growth of the appropriate temperature of 20C ~ 30C, not cold, 10C below the growth of slower.
Spring, summer and fall blooming, long flowering period and high ornamental value, good adaptability to soil conditions, drought tolerance, medium water requirements.
Three: reproduction technology
Willow leaf verbena mainly using seed propagation, especially in the northern region of China, early spring in the solarium or automated greenhouse with protective facilities for seedling, can greatly extend the flowering of the ornamental period of the - year.
(1) germination requirements
Willow leaf verbena seeds about 4000 per gram, the germination rate of about 85%. Seed germination temperature 20C~25C, 9~15d germination after sowing.
(2) Sowing requirements
Because of the small seeds of Verbena willow leaf, seedling nursery in the early stage of the 200-hole hole tray nursery, in order to save space and easy to manage, 40d after sowing can be based on the growth of seedlings and planting time poured into the 72-hole or 50-hole hole tray. Seedling medium can be imported from Denmark to ensure that the seedling growth is neat and healthy. 72 or 50 hole hole hole tray root system full disk, the true leaves to reach 4 to 6 pairs and the root system into a group, can be directly planted.
Willow verbena can also be propagated by cuttings, take cuttings of the terminal buds of the planted seedlings, cuttings of rooted seedlings can be formed after 1 month.
(3) Cultivation management
Willow verbena in the cultivation process, in order to prevent stagnant water caused by plant rot and death, flat land is best made into a high ridge planting, if the soil is too viscous or saline high too thin, before planting should be applied to humus on the improvement.
Before planting, according to the soil and terrain to determine the reasonable spacing between plants, in general, willow verbena plant spacing in the 30 ~ 40cm, row spacing 40 ~ 60cm is appropriate.
After planting, in order to promote branching, control plant height, can be centering.1~2 times, the first centering should be left 4~6 pairs of leaves, centering is too low, affecting the number of lateral branch growth. During normal growth, the amount of watering must be careful not to be too diligent and too large, otherwise the plant is easy to grow in vain, disease resistance and poor resistance to collapse.
(4) Pest control
Pest management
The dry early season is mainly harmed by red spiders and thrips. Red spider can be controlled by spraying 40% dicofol emulsion 1000~1500 times, 20% mite death net wettable powder 2000 times, 15% pyridaben emulsion 2000 times, all of which have good control effect. Thrips can be prevented by 5% aminopyralid wettable powder 2,500 times, 1.8% abamectin emulsion 3,000 times, or fluvalinate, mevinphos, and high efficiency cyfluthrin. Spraying every 5~7d, 3 times in a row, can get good control effect. Focus on spraying young tissues such as flowers, young leaves and young fruits.
Iron deficiency
Iron deficiency or pH value higher than 6.8 will lead to the upper surface of the leaves appearing foliage green phenomenon, can be increased by applying ferrous sulfate to reduce the pH value. Now commonly used 1500 times Zhixin iron fertilizer spraying or watering the soil, 2~3 times after the symptom has obvious improvement, or application of our company formulated aohe iron 300 times liquid watering the soil, the prevention and control effect is better.
Four: planting precautions
Sowing seeds without covering, but pay attention to the substrate moisturizing; willow verbena seedling temperature requirements, room temperature should be higher than 18C, lower than 16C seedling time will be prolonged, the seedling rate is reduced.
The seedling period should increase light, reduce humidity, so as to avoid seedling growth, growth period should be supplemented with iron, magnesium fertilizer, to prevent deficiencies, late density is too large, can be appropriate to remove some of the plants.