Can houttuynia cordata be planted in summer?

1. Description of the morphological characteristics of Houttuynia cordata Thunb.

Houttuynia cordata Thunb It belongs to clover in Cruciferae, and is usually called big leaf root, centella asiatica and mustard. Perennial herbs, 30 ~ 50 cm high, the whole plant has a stench; The upper part of the stem is erect, often purplish red, the lower part is creeping, and the nodes are whorled with small roots. Leaves alternate, papery, with glandular spots, especially on the back, oval or wide oval, 4 ~ 10 cm long and 2.5 ~ 6 cm wide, heart-shaped base, entire, often purplish red on the back, 5 ~ 7 palmate veins, petiole 1 ~ 3.5 cm long, hairless, and stipules 650 cm long. Flowers are small, open in summer, without perianth, arranged opposite to leaves in spikes, about 2 cm long, with 4 total bracts, born at the top of the total pedicel, white, petal-shaped, 1 ~ 2 cm long, 3 stamens, long filaments, and the lower part of the filaments is combined with the ovary. The pistil consists of 3 syncarps. Capsule nearly spherical, 2 ~ 3 mm in diameter, cracked at the top, with persistent style. Seeds numerous, ovate. The flowering period is from May to June, and the fruiting period is10-165438+1October. 2. Biological characteristics of Houttuynia cordata Thunb.

Houttuynia cordata is mainly distributed in Shaanxi, Gansu and the provinces and cities south of the Yangtze River basin, and is born in wet or low-lying places near water, hillsides and roadsides. Prefer warm and humid environment and avoid drought. Cold-resistant, afraid of strong light, can overwinter at-15℃. It blooms in April-May and bears fruit in June-July. Xie Miao/kloc-0 started in late October, 165438+, and turned green in March of the following year. Fertile sandy loam and humus loam grow best in soil, which is not suitable for clay and alkaline soil planting. 3. Cultivation techniques of Houttuynia cordata Thunb.

(1) land selection and preparation

Choose loam or sandy loam with flat terrain, sufficient moisture, convenient irrigation and drainage, deep soil layer and fertile soil for planting, and dig deep into the soil. Before planting, apply 2000-3000 kg of fully decomposed farm manure and 30-50 kg of NPK compound fertilizer, and then shallow till (15-20 cm) the soil to make the fertilizer and soil evenly mixed.

(2) Breeding methods

Because the germination rate of Houttuynia cordata seeds is not high, asexual propagation is mainly used in field production. Asexual propagation can be divided into ramet propagation, cutting propagation and rhizome propagation. The ramet propagation is to dig out the mother plant and transplant it into sandy soil from late March to April; Cutting propagation: In spring and summer, healthy branches without plant diseases and insect pests are used as cuttings, cut into 12- 15 cm with 3-4 sections, soaked in rooting agent No.3 solution with a concentration of 500 ml/kg for 10 second, and pressed10 */kloc-0. Rhizomes propagate in spring and autumn. Select healthy underground rhizomes without pests and diseases, and cut them into about 5- 10 cm with a sterilized knife as seed stems. According to the plant spacing of 15 cm, lay it flat in the prepared furrow and cover it with 6-7 cm thick fine soil. Water and irrigate in time after planting to ensure the soil surface is moist. /kloc-can germinate in 0/5-20 days.

(3) Site management

1, intertillage weeding: from seedling survival to line closure, intertillage weeding should be done for 2-3 times, and weeds should be pulled out manually without intertillage at a distance of 5 cm from plant roots. The herbicide can be 70-75 ml of 50% acetochlor EC, and 40-45 kg of water is added and sprayed evenly on the border.

2. Timely irrigation: Houttuynia cordata likes humidity and is afraid of drought, and different seasons and different growth periods have different requirements for water; Seedlings are not easy to emerge after sowing, so reasonable irrigation is needed to ensure that the seedlings are neat and strong. After emergence, the soil should be kept moist throughout the growth period. The early growth stage of Aconitum kusnezoffii is in dry season, especially in areas with severe spring drought such as Yunnan. In order to ensure the normal growth and development of Houttuynia cordata Thunb, it is advisable to keep the relative water content of the soil at about 70%, and do not air-dry, otherwise it will lead to more fibrous roots, low yield and poor quality, so irrigation should be carried out according to the weather, land and seedling conditions.

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3. Rational topdressing: In the case of sufficient base fertilizer, topdressing is needed for 2-3 times in the whole growth period. When the seedling height is 5- 10 cm after emergence, the first topdressing is furrowing between the rows of houttuynia cordata Thunb. , and deeply apply urea in the ditch, covering the soil, and the dosage of urea per mu is 10- 15 kg to promote the rapid growth of seedlings. The second topdressing is carried out in the vigorous growth period, and the method is the same as the first one. The type and dosage of fertilization are urea15-20kg and potassium sulfate 8 8- 10/0kg. The third topdressing is carried out at booting stage and early flowering stage, and the method is the same as above. The types and dosage of fertilizers are urea12-20kg, potassium sulfate10-15kg and calcium superphosphate 20-30kg.

Fertilization should be carried out according to the situation of seedlings, and if the seedlings grow badly, the number of fertilization can be increased appropriately; On the contrary, the seedlings grow vigorously, and the number of fertilization can be reduced appropriately. (5) Pest control

There are few pests and diseases in the whole growth period of Houttuynia cordata, and the main pests and diseases are white silk disease, purple spot disease, black cutworm, Spodoptera litura and red spider.

1, white silk blight: it mainly harms the stem base and underground stem of plants. At the early stage of the disease, the aboveground stems and leaves turn yellow, the surface of underground stems is covered with white filamentous hyphae, and yellowish brown to brown soft rot appears at the base and rhizome of stems. In the middle and late stage, a large number of sclerotia were produced in the stems covered with mycelium and nearby soil. Sclerotinia sclerotiorum is a small white spherical particle at the initial stage of formation, and turns yellow-brown to brown after aging. In continuous rainy weather, obvious white hyphae and sclerotia can be seen around the surface of the diseased plant; Later, the whole plant withered and died.

Control method: Rotation with aquatic crops (rice, etc.). ) Paddy field and dry land, before planting, mix fine soil with carbendazim or chlorothalonil and apply it on the border for disinfection. If the diseased plants are found, they should be pulled out in time, and sprayed with 20% triadimefon EC 65,438+0,500 times or 40% dimethachlon WP 800 times continuously for 2-3 times with an interval of 7-65,438 times each time.

2. Purple spot disease: mainly harms leaves. At the early stage of the disease, lavender spots appeared on the leaves. After expansion, the lesion is oval with obvious concentric wheel lines, and the edge is sometimes not obvious. The wheel line is gray. There are 1-3 purple rings on the front of leaf lesion. In the middle and late stage, the lesion is perforated, and several lesions are connected to form an irregular shape. The diseased leaves will eventually dry up and die. A mildew layer grows on the diseased spot, and when it is serious, the whole leaf surface is covered with diseased spots and dies.

Control method: rotate with gramineous crops, soak seeds with 500 times solution of 50% carbendazim powder for 5- 10 minutes before sowing, and pull out diseased plants in time. At the initial stage of the disease, 70% mancozeb 500 times solution or 50% iprodione wettable powder 1000 times solution was sprayed continuously for 2-3 times with an interval of 7-65430.

3. Black cutworm: it mainly harms the young leaves of Houttuynia cordata Thunb. At a younger stage, it usually hurts young leaves and bites them into pits, holes or nicks. After the third instar, the larvae dive into the surface of the soil and bite off the roots, underground stems or tender stems near the ground, resulting in seedling shortage and ridge breakage when the damage is serious.

Control methods: rotation of paddy and upland crops, timely removal of weeds in the field, deep ploughing of soil (more than 30cm) before planting, sun drying, treatment with phoxim mixed with fine soil and toxic soil, and root irrigation with 2.5% triadimefon 6000 times solution or 40% Leshi EC 16 when the population density in the field is high.

4. Spodoptera litura: Larvae damages leaves and tender stems of Houttuynia cordata Thunb, feeds on leaves, produces nicks and holes, excretes feces, and causes pollution and decay.

Prevention and control methods: Before planting, dig deep into the soil (more than 30cm) to dry the field, mix phoxim and fine soil toxic soil for treatment, and spray 2,500 times of 5% Regent emulsion and 3,000 times of 2.5% Uranus emulsifiable concentrate for continuous prevention and control for 2-3 times with an interval of 7- 10 day.

5. Starscream: Young, weak and adult mites suck juice on the leaves of Houttuynia cordata Thunb. , and gray or yellowish brown spots appear. In severe cases, the leaves will turn yellow and fall off.

Control method: clear weeds in the field in time. When the population density is high, spray with 2000 times of 15% pyridaben for 2-3 times continuously, with an interval of 7- 10 day. Fourth, harvesting and processing.

Houttuynia cordata can be harvested in the first year of planting and after the first year. It can only be harvested once in the first year of planting, that is, September -65438+ 10 in autumn, when the stems and leaves are lush, there are many flowers and the smell is the strongest, and it is harvested in June in previous years.

And harvest once in September -65438+ autumn 10. The harvesting method is that after the dew is dried in the sun on a sunny day, the above-ground parts are cut evenly, and after the above-ground parts are harvested in the autumn of the following year, the underground roots are dug, which can be sold as edible vegetables. The medicinal parts are collected, washed and dried, and used as underground roots of vegetables for cleaning.