What is crape myrtle

Lagerstroemia speciosa (dicotyledonous plant of Lagerstroemia of Lysimachiaceae)

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[zǐwüI]

Lagerstroemia indica (scientific name: Lagerstroemia indica), also known as itch flower, prurigo, purple flower, purple orchid, mosquito flower, Myrica rubra, zinnia and skinless tree, is a deciduous shrub or small tree, belonging to Litchi family. Of southern Asia and northern Australia. Lagerstroemia indica has beautiful posture, smooth trunk and bright colors; It is in summer and autumn when it blooms, and the flowering period is extremely long, from June to September. Therefore, it is called "Hundred Days Red" and has the reputation of "Summer Blue and White Flowers Full". It is a good bonsai for flowers, stems and roots, and it is cultivated in many places in China. (Basic information column source: [1])

catalogue

Morphological characteristics of 1

2 place of origin

3 medicinal value

4 garden viewing

5 cultivation techniques

Breeding mode

Cultivation method

control of insect

6 plant culture

Arima

One legend is that ...

Poetry article

city flower

Morphological characteristics of 1

crape myrtle

Deciduous shrubs or small trees, up to 7 meters high; Bark is smooth, gray or grayish brown; Branches twisted, branchlets slender, 4-angled, slightly winged. Leaves alternate or sometimes opposite, papery, oval, broadly oblong or obovate, 2.5-7cm long and 65438 0.5-4cm wide, short or blunt at the top, sometimes slightly concave, broadly wedge-shaped or nearly round at the base, hairless or puberulent below the midvein, with 3-7 pairs of lateral veins and no obvious veinlets; Sessile or petiole very short. Flowers are red or purple, white, 3-4 cm in diameter, usually forming a terminal panicle of 7-20 cm; Pedicel 3- 15 mm long, axis and pedicel pilose; The calyx is 7- 10 mm long, and the exterior is smooth without edges, but when it is fresh, the edge of the calyx tube is short, with microprotrusions, hairless on both sides, and the lobes are 6, triangular, upright and without appendages; Petals 6, shriveled, long 12-20 mm, with long claws; Stamens 36-42, 6 are inserted on the calyx outside, much longer than others; Ovary 3-6-loculed, glabrous. The capsule is ovoid, spherical or broadly elliptic, with a length of 1- 1.3 cm, green to yellow when it is young, purple-black when it is mature or dry, and its ventral part is cracked. Seeds winged, ca. The flowering period is from June to September, and the fruiting period is from September to June. [2]

2 place of origin

China's Guangdong, Guangxi, Hunan, Fujian, Jiangxi, Zhejiang, Jiangsu, Hubei, Henan, Hebei, Shandong, Anhui, Shaanxi, Sichuan, Yunnan, Guizhou and Jilin have all grown or cultivated; Semi-shady, like to be born in fertile and humid soil, but also drought-tolerant, calcareous soil and acidic soil grow well. Originated in Asia, it is now widely planted in tropical areas. [2]

3 medicinal value

crape myrtle

Lagerstroemia indica has medicinal effects, which Li Shizhen discussed in Compendium of Materia Medica. Its bark, wood and flowers have the functions of promoting blood circulation, dredging menstruation, relieving pain, reducing swelling and detoxifying. Seeds can be used as pesticides to kill pests. Leaves can cure white dysentery, flowers can cure postpartum hemorrhage, children's rotten head and fetal poison, and radically cure carbuncle, swelling and sore poison, which can be described as treasure all over.

Source: Lagerstroemia indica, a Lagerstroemia plant with roots and skin as medicine. Picking peeled bark in summer and autumn and drying; Roots can be taken at any time.

Tropism of nature and taste: slightly bitter, astringent and flat.

Indications: promoting blood circulation, stopping bleeding, detoxicating and reducing swelling. Used for various bleeding, fracture, mastitis, eczema, hepatitis and ascites due to liver cirrhosis.

Usage and dosage: 25 ~ 100g.

4 garden viewing

The tree has bright and beautiful colors, long flowering period and long life span, and the tree age is 200 years. Now they are widely cultivated as garden ornamental trees, and sometimes as potted plants in tropical areas.

Lagerstroemia indica [3]

Scene. Lagerstroemia indica wood is hard and corrosion-resistant, and can be used as materials for farm tools, furniture and buildings. Bark, leaves and flowers are strong laxatives; Genpi decoction can treat hemoptysis, hematemesis and hematochezia.

Lagerstroemia indica, as an excellent ornamental tree species, is widely used in park greening, courtyard greening, road greening, block cities and so on. In practical application, it can be planted in front of buildings, courtyards, Chi Pan, rivers, lawns and on both sides of park paths. It is also a good material for making bonsai.

5 cultivation techniques

Breeding mode

Breeding mainly adopts the methods of sowing and cutting.

Lagerstroemia speciosa

Meristem, layering and grafting can also be used. [4]

A large number of healthy and tidy seedlings can be obtained by sowing and raising seedlings once. 165438+ 10 ~ 65438+February, collect mature seeds, remove the peel, slightly dry the seeds, and put them in a container for drying and preservation. In March of the following year, the sandy loam seedbed was planted with wide banners or spread, covered with a layer of fine burnt marl and covered with grass, so that no seeds could be seen. Germinate for more than 10 days, uncover the grass in time, and sow after the rain when two pairs of true leaves appear; Weed frequently in seedling stage, topdressing 2 ~ 3 times in June ~ July, irrigation in summer to prevent drought, the height of seedlings at the end of the year is about 40 ~ 50 cm, and they can bloom in the same year when they grow vigorously, so they should be cut off in time and transplanted and grown up in the spring equinox the following year. [4]

Cutting propagation Cutting propagation can be divided into hard branch cutting and soft branch cutting. [4]

Hardwood cutting is generally carried out in the middle and late March to early April before the branches germinate. Select stout annual branches, cut them into cuttings with a length of 15cm, and insert them into a loose and well-drained sandy loam seedbed. The cutting depth shall be subject to exposing the top buds of the cuttings. After insertion, it is filled with water and covered with plastic film to keep moisture and heat. When the seedlings grow to 1.5 ~ 20 cm, the film can be uncovered, replaced with sunshade nets and watered in time, and the branches can grow to about 60 ~ 80 cm in that year. [4]

Softwood cutting is carried out in July and August, when the new branches grow vigorously and have the most vitality. Select semi-lignified branches and cut them into cuttings with a length of 8 ~ 10 cm, leaving 2 ~ 3 leaves at the top. The cutting depth is 3 ~ 4cm. After inserting, you can water it and shade it with a shade shed. Generally, it can take root in about 20 days. Remove the film, keep the sunshade net, and then water it in time. Branches can grow to about 60 ~ 80 cm in that year, and the survival rate is very good. [4]

In meristem propagation, the roots of tillering seedlings germinated in the rhizosphere of plants are dug out, roots and branches are properly pruned and planted separately. Small seedlings can be bare-rooted, and big seedlings should carry mud balls. During the tending period, they should be pruned and trimmed frequently to maintain a beautiful tree shape and promote the flourishing of flowers and branches. [4]

Stratified propagation Stratified propagation can be carried out in the whole growing season of Lagerstroemia indica, especially in March-April in spring. In the air layering method, branches of 1 ~ 2 years old can be selected, cut and girdled with a sharp knife to expose xylem, and rooting powder solution can be applied about 3 cm above the cut part (diluted according to regulations). When it is dry, put a cylindrical plastic bag around the cut part, fill it with loose garden soil, water it and tie it tightly at both ends, and check it after one month. If the soil is too dry, it can be hydrated and moisturized. [4]

There are several varieties of grafted Lagerstroemia indica, such as Yin Wei, whose flowers are white; Cuiwei, the flowers are blue-purple and lavender; Red, pink, crimson, etc. ; Several annual or biennial branches with different colors are grafted on the same tree, and the survival rate is above 98%. The specific method is: from late February to early March, before the branches of Lagerstroemia indica sprout. When grafting, the well-developed seedlings are selected as rootstocks, and the branches of the required color are used as scions, and the splitting method is adopted. First, the top of the rootstock near the periphery is split longitudinally with a knife with a depth of about 5-8 cm, and then the scion with more than 2 buds with a length of 5-8 cm is cut into a wedge shape and inserted into the split part of the rootstock to align with the cambium. Then wrap the whole spike with plastic film to expose the bud head. This method is used to graft branches of different colors on the same rootstock in layers to form multi-color trees. After 2 ~ 3 months of grafting, the film can be loose, and the length of earlobe can reach 50 ~ 80 cm. Branches should be cut short in time to avoid being broken by the wind and can be cultivated into thick branches. The survival rate of plants cultivated in this way is very good. [4]

Cultivation method

Lagerstroemia indica should be planted in the leeward and sunny place with deep soil layer, fertile soil and good drainage. Large seedlings should be transplanted with soil balls and properly trimmed branches, otherwise the survival rate is low. Apply decomposed organic fertilizer as base fertilizer in the planting hole, water it after cutting, and water it 1 time after 3 days. Lagerstroemia indica germinates late. Under normal circumstances, the leaves will only spread from mid-April to the end of April. Because of root injury, the germination of new plants will be delayed. So don't give up management just because you have no job. [4]

After survival, the plant management is extensive, Lagerstroemia indica has strong vitality and is easy to plant.

crape myrtle

Cultivation is not strict with soil, but it grows best in deep and fertile sandy loam. Sex likes light, so it should be planted in the lee of the sun or under the roots of the south wall of the courtyard. If the light is insufficient, plants will not only spend less or not, but even grow weak and have small branches and leaves. Lagerstroemia indica is cold-resistant, but it should be well protected from cold and heat at seedling stage, and the adult plants over three years old do not need heat preservation. Lagerstroemia indica is drought-tolerant and afraid of waterlogging. Water it once a year before germination in spring and after defoliation in autumn. If it is not too dry at ordinary times, you don't need to water it. Generally, water l ~ 3 times in spring drought, and drain well in rainy season to prevent water from rotting roots. Autumn is not suitable for watering. Fertilization can be applied after defoliation in winter and before germination in spring every year, such as applying human manure or sesame paste residue, which can make plants grow vigorously and flowers big and colorful in the coming year. In order to make Osmunda bloom, pruning should be carried out during dormancy. Because the crape myrtle inflorescence is planted at the top of the new branches in that year, the annual branches should be pruned and retracted when pruning, so that the nutrients are concentrated and the branches are strong. Long branches, dead branches, drooping branches, pests and diseases branches, slender branches and endogenous branches should be cut off, and the side branches at the lower part of the trunk should be cut off in time during the young tree period, so that the upper part of the trunk can get enough nutrients and form a good crown. [4]

Lagerstroemia indica cultivation and management are extensive, but it is necessary to cut off dead branches, pests and diseases in time and burn them. In order to prolong the flowering period, the branches that have blossomed should be cut off in time so as to germinate again and grow the next round of flowers. In order to make the trunk thicker, you can cut off many flowers and concentrate on cultivating the trunk. Practice has proved that Lagerstroemia indica can bloom many times a year as long as it is properly managed, as long as 100 ~ 120 days. [4]

Maintenance points

1. Strengthen the light. Lagerstroemia indica likes sunshine, so it must be placed in a sunny place outdoors during the growing season. [5]

2. Water it in time. Pot soil should be kept moist in spring and winter, and watered once every morning and evening in summer and autumn. In case of drought and high temperature, the daily watering frequency can be appropriately increased, and river water, well water, rainwater and tap water should be stored for 2 ~ 3 days. [5]

3. Fertilize regularly. Too much fertilization on potted Lagerstroemia indica is easy to cause white branches and leaves. If the lack of fertilizer leads to thin branches and yellow leaves, the whole plant will grow weakly, with few or no flowers. Therefore, it is necessary to apply fertilizer regularly, apply more fertilizer in spring and summer peak season, and apply less fertilizer after autumn. There is no need to apply fertilizer when winter enters the dormant period. Don't fertilize at noon in rainy days and summer when the temperature is high. Fertilization concentration is applied every 10 day from beginning of spring to beginning of autumn, topdressing every half month after beginning of autumn, and fertilization is stopped after beginning of winter. [5]

4. reasonable pruning. Lagerstroemia indica is resistant to pruning, with strong branching ability and large growth of new shoots. Therefore, after flowering, residual flowers should be cut off to prolong the flowering period, and long branches, overlapping branches, cross branches, radiation branches and diseased branches should be cut off at any time to avoid consuming nutrients. [5]

5. Change pots in time. Potted Lagerstroemia indica is replaced every 2-3 years, and 5 parts of loose mountain soil, 3 parts of pastoral soil and 2 parts of fine river sand are mixed to make culture soil. When changing pots, organic fertilizers such as bone meal and bean cake powder can be used as base fertilizer, but the fertilizer can't directly contact the root system, so as to avoid damaging the roots and affecting plant growth. [5]

control of insect

Lagerstroemia indica is a kind of landscaping tree species susceptible to diseases and insect pests. As far as Tianshui area is concerned, it is the most suitable place for Lagerstroemia indica to grow because of its beautiful scenery and pleasant climate. However, in the long-term cultivation and management process, we also found many problems. Below, the occurrence regularity and control methods of some main pests and diseases of Lagerstroemia indica are introduced as follows.

Powdery mildew of Lagerstroemia indica

Control of Lagerstroemia indica pests and diseases

Powdery mildew is a worldwide disease with a wide range of hosts, and Lagerstroemia indica is its 1 important target. Powdery mildew of Lagerstroemia indica is widespread in the provinces and cities where Lagerstroemia indica is planted in China. After the disease occurs, the leaves of Lagerstroemia indica often turn yellow and fall off, which directly affects the tree potential and ornamental effect. [6]

Powdery mildew is a fungal disease, which mainly harms leaves. Young leaves are more susceptible to infection than old leaves. The disease also harms branches, shoots, buds and buds. At the early stage of the disease, small white speckles appeared on the leaves, which became round or irregular faded spots after expansion, covered with a layer of white powdery mildew, and turned gray in the later stage. After the flowers are infected, the surface is covered with white powder, and the flower spikes are deformed, losing ornamental value. The plants affected by powdery mildew will become shorter, the tender leaves will be twisted and withered, the leaves will become smaller without spreading, and the branches will be deformed. If it is serious, the whole plant will die. [6]

Occurrence law

Powdery mildew of Lagerstroemia indica overwinters on diseased buds, diseased branches or fallen leaves. When the temperature is suitable in the next spring, the overwintering hyphae begin to grow and develop, producing a large number of conidia, which spread and infect with the airflow. In Tianshui area, the disease usually begins in April and tends to be serious in June. It will slow down or stop in July and August because of the hot weather, but it may reappear in September to 65438+ 10. Powdery mildew occurs seriously in rainy season or under high relative humidity. Partial application of nitrogen fertilizer, too dense planting of plants or poor ventilation and light transmission are all beneficial to the disease. [6]

Prevention and control methods:

(1) Gardening has a strong ability to prevent Lagerstroemia indica from sprouting branches, so for plants with serious diseases, all the branches of that year can be cut off and burned in winter, thus completely eliminating the source of the disease. If Lagerstroemia indica planted at home is found to be infected with powdery mildew, the diseased leaves should be removed in time and the potted flowers should be placed in a ventilated and light-transmitting place. In field cultivation, it is necessary to control planting density, strengthen daily management, pay attention to increasing the application of phosphorus and potassium fertilizer, control the application amount of nitrogen fertilizer, and improve the disease resistance of plants; At the same time, we should also pay attention to the selection of disease-resistant varieties. [6]

(2) When the chemical control condition is serious, the mildew-breaking 3 ~ 4 stone sulfur mixture can be sprayed before germination in spring; When the disease occurs in the growing season, it can be prevented by spraying 500 times 80% zineb wettable powder, 1000 times 70% thiophanate-methyl, 1500 times 20% triadimefon emulsifiable concentrate or 800 times 50% carbendazim wettable powder. [6]

Lagerstroemia indica brown spot

Brown spot disease is also a common disease of garden plants, which often occurs in the growing season of Lagerstroemia indica. The occurrence of brown spot disease often leads to a large number of dead leaves and fallen leaves of plants. Affect viewing and flowering. [6]

Show symptoms

The pathogen of Lagerstroemia indica brown spot is also fungi, which mainly invades leaves. Usually, the lower leaves begin to get sick and then gradually spread to the upper parts. At the beginning of the disease, the lesions were round or nearly round, with different sizes and a few irregular shapes. The focus is purple-black to black with light edge color. Then the color of the lesion deepened, showing black or dark black, and the boundary with the healthy part was obvious. In the later stage, the color of the lesion center becomes pale and small gray-black mildew spots appear. When the condition is serious, the diseased spots become one piece, the whole leaves turn yellow quickly and fall off early. [6]

Occurrence law

Lagerstroemia indica brown spot is caused by Cercospora lutea infection. The pathogen overwinters in the form of mycelium or conidia, and in the second year, it is infected and reinfected by conidia for the first time, and it is spread by airflow or wind and rain. Brown spot disease in Tianshui area generally begins in early summer and is seriously harmful in autumn. It is easy to break out in hot and rainy seasons, especially in years or seasons with frequent rainstorms; Generally speaking, the lower leaves are more susceptible to infection than the upper leaves. [6]

Prevention and control methods:

(1) Early detection of horticultural control, timely removal of diseased branches and leaves, centralized incineration or deep burial, and reduction of pathogen sources. Strengthen cultivation management, plastic pruning, so that plants are ventilated and transparent. It is best to change the soil for family potted plants every year. [6]

(2) At the initial stage of chemical control, 500 times of 50% carbendazim wettable powder, 65% zineb wettable powder 1000 times or 800 times of 75% chlorothalonil wettable powder can be sprayed for control. [6]

Sooty blotch, Wei Zi

Sooty blotch, also known as soot disease, is widespread among garden plants in China. The invasion of Lagerstroemia speciosa is mainly due to the harm of Lagerstroemia speciosa and Lagerstroemia speciosa, that is, the mucus secreted by them is used as nutrition to induce a large number of bacteria polluting coal to multiply. After the disease, the leaves of diseased plants are covered with black mold layer, which not only affects the ornamental value of Lagerstroemia indica, but also affects the photosynthesis of leaves, resulting in the weak growth of plants and early defoliation. [6]

Show symptoms

The pathogen of Lagerstroemia indica black spot belongs to fungi, but there are many kinds of pathogens of black spot. The same plant can be infected with a variety of pathogenic bacteria, and its symptoms are slightly different, but the black mold layer or black pulverized coal layer is an important feature of the disease. Sooty blotch mainly attacks leaves and branches. The disease first infects the front of the leaf along the main vein, and then gradually covers the whole leaf surface. In severe cases, the surface of leaves, branches and even petioles will be covered with black coal powder, which will block the stomata of leaves and hinder normal photosynthesis. [6]

Occurrence law

Sooty blotch pathogens overwinter in diseased leaves and branches in the form of mycelium or ascomycetes. Because the mucus secreted by Lagerstroemia indica and Lepidoptera Lagerstroemia indica will provide nutrition for pathogenic bacteria in sooty blotch, generally, after the occurrence of these two pests, sooty blotch will occur in large numbers. However, from late June to early September, the damage of Lagerstroemia speciosa and Lagerstroemia speciosa reached its peak, and the high temperature and humidity at this time were also conducive to the occurrence of the disease. Therefore, spring (caused by overwintering bacteria) and autumn (caused by Lagerstroemia speciosa and Lagerstroemia speciosa) are the heyday of sooty blotch, and 1 ~ 2 generation occurs in Tianshui area 1 year. [6]

Prevention and control methods:

(1) Horticultural control

(1) Make trees ventilated and transparent by measures such as thinning seedlings and pruning;

(2) timely control aphids, scale insects, whiteflies, etc. Because the secretion of these insects is the basis of the existence of pathogens in sooty blotch. [6]

(2) Lime-sulfur mixture is commonly used in chemical control, with Pomei-3 lime-sulfur mixture in winter and 0.3 lime-sulfur mixture in summer and autumn. It can also be controlled by phosphorus trichloride and litsea cubeba leaf juice. Or spray 500-800 times of 50% carbendazim wettable powder and 500 times of 70% thiophanate methyl. [6]

Lagerstroemia indica

In northern China, 5 ~ 8 generations occur every year, and the eggs overwinter near the buds, with May as the initial stage of the disease and June as the peak. Nymphs and adults cluster to harm young leaves and suck juice, which affects growth and development. [6]

Prevention and control methods:

Scrape off the old bark, cut off the damaged branches in early spring, and burn them centrally to eliminate the overwintering eggs. [6]

Strengthen cultivation management measures to reduce the source of disease. [6]

When the aphid quantity is large, cough 40% omethoate, 40% acephate 1000 ~ 1500 times or spray dementin 1000 ~ 2000 times, but pay attention to avoid phytotoxicity. [6]

Natural enemies, such as harmonia axyridis, grass ridge larvae, etc., are artificially propagated and dispersed in places where conditions permit. [6]

Trap and kill winged aphids with colored plates or reflect light with white tin foil, refusing to live and migrate. [6]

6 plant culture

Arima

Addicted to love, lucky, eloquent, female.

One legend is that ...

There is a legend about the origin of osmanthus in China. In ancient times, there was a fierce beast called Nian, which hurt countless people and animals. So the purple star came down to earth, locked it in the mountains and allowed it to go out only once a year. In order to supervise for one year, Ziweixing turned into Ziweixing and stayed in the world, bringing peace and beauty to the world ... Legend has it that if your home is full of Ziweixing, Ziweixian will take care of you and give you happiness all your life.

Poetry article

It's better to be infatuated, but exposure to pressure and bullying is particularly inclined. Who said that flowers bloom for a hundred days and crape myrtle grows for half a year? -Song Dynasty. Yang Wanli

Bai Juyi's Wei Zihua

A Floating Life and Wisdom-Wei Zi [7] (Huang Ting French)

city flower

Lagerstroemia indica is regarded as the city flower in some places.

Lagerstroemia indica is the city flower of Anyang City, Henan Province [8], also known as skinless tree and full house red, and it is a widely planted ornamental tree species in urban areas.

Lagerstroemia indica is also the city flower of Tai 'an City, Shandong Province, also known as Melaleuca, belonging to Chrysophyceae, and is a deciduous shrub or small tree. There is a crape myrtle tree in the courtyard of Luohanya, which is nearly a hundred years old. Its trunk is as long as a dragon pan and full of ancient meaning. Every year from summer solstice to autumn, flowers bloom like fire, the breeze blows, and Jiao Jiao trembles, which is beautiful. Tai 'an Municipal Government planted Lagerstroemia indica in streets, courtyards and scenic spots of Taicheng, and designated it as the city flower.

Ziwei is also the city flower of Xuzhou, Jiangsu. Lagerstroemia indica is also called itchy flower. When you gently grasp the branches with your fingers, the whole plant will tremble slightly, as if it were ticklish. Lagerstroemia indica is widely planted on both sides of roads in Xuzhou, making Xuzhou, a famous historical and cultural city, more beautiful and lively.

Lagerstroemia indica is also the city flower of Zigong City, Sichuan Province, also called itchy flower, which can be seen everywhere in Zigong.

Lagerstroemia indica is the city flower of Xiangyang City, Hubei Province. Xiangyang is one of the regions with the largest variety of Lagerstroemia indica in China, and there are a large number of wild plants in the mountainous areas of Baokang and Nanzhang counties under its jurisdiction. The oldest tree is over 1000 years old and is the tallest in China.

Wei Zi is the city flower of Jintan City, Jiangsu Province.

Wei Zi is also the city flower of Yantai.

Wei Zi is also the city flower of Jiyuan City, Henan Province.