Production and maintenance of crape myrtle bonsai

Crape myrtle is a good bonsai material for viewing flowers, trunks and roots, also known as startled trees, hundred-day red, full-house red, itchy trees, etc., for the deciduous shrubs or small trees of the family Celastraceae, with graceful trees, smooth and clean trunks, bright flowers and colors, with high ornamental value. Let's take a look at the production and maintenance of crape myrtle bonsai.

Growth habits of crape myrtle

Crape myrtle likes warm and humid climate, light, shade and fertilizer, especially deep and fertile sandy loam, born in slightly humid places, drought-resistant, waterlogging-resistant, warm and cold-resistant, strong sprouting, strong anti-pollution, and strong resistance to sulfur dioxide, hydrogen fluoride and chlorine. Semi-shady, happy to be born on fertile and moist soil, can also tolerate drought, no matter calcareous soil or acid soil grows well.

The production of crape myrtle bonsai

1. Grafting and replacement: the root system of crape myrtle is well developed, and it is extremely easy to produce new roots after root cutting, and it is easy to survive in the pot. When the ideal crape myrtle pile head is obtained, it should be cut and pruned according to the needs of bonsai modeling. if the pile head with better root system can be planted in the pot directly, the thicker branches can be cultivated to facilitate the survival of grafting. General habit is carried out before sprouting in spring, in fact, different grafting methods can be used, which can be grafted all the year round and can be repaired many times according to the survival of grafting.

2. Mountain excavation: crape myrtle excavation time is generally from early October to early spring before sprouting, we should try to avoid the cold season and dry weather. When digging, take the old pile head with sturdy roots, strange twists or hollow trunks, shaped like wrinkled and leaky stones, etc., dig them up, plant them directly in the basin, or plant them in moist, fertile, loose and breathable soil, wait for the root system to resume growth, and then move into the basin when the branches and leaves are luxuriant.

3. Pot planting: when crape myrtle bonsai is put on the pot, it will be arranged according to the shape of the pile head of crape myrtle bonsai and the needs of future modeling. Then pour the prepared loose and fertile humus loam around the basin to make its roots and soil dense, pour enough fixed root water, and place it in a leeward shade for maintenance. Usually, you should spray water to the branches to moisturize, prevent the trunk from drying, and move to the sun after sprouting for normal maintenance.

Maintenance of crape myrtle bonsai

1. Reasonable watering: at the initial stage of crape myrtle branch and leaf growth, it is necessary to properly control the amount of watering and control the growth of crape myrtle bonsai branches and leaves, so that the branches are stout and the leaves are small, so that the large nodes of leaves are avoided and the control of tree shape is seriously affected. watering should be sufficient after budding to the flowering stage, and the amount of water should be increased in the summer high temperature and drought season. Water should be sprayed regularly on the crown leaves to increase air humidity, reduce watering in winter, and the basin soil should be slightly dry.

2. Timely fertilization: crape myrtle bonsai is mainly applied with sufficient basic fertilizer in winter, and cake liquid fertilizer and other phosphate-free potassium fertilizer should be applied once a week during the growing period. 0.2% potassium dihydrogen phosphate solution can be used for foliar spraying before and after budding to promote flower bud differentiation and bud expansion. It is necessary to apply sufficient basal fertilizer after each flower. In particular, the formed crape myrtle bonsai, when blooming to 2 or 3 times in the same year, must be combined with pruning and shaping, and it is particularly important to apply sufficient basic fertilizer, otherwise there are branches without flowers, or flowers are rare, flowers are not colorful, and the best ornamental effect can not be achieved.

3. Turn the basin and change the soil: the crape myrtle bonsai should be determined according to its growth potential, turn the basin and change the soil every 2-3 years, and change the basin in winter and spring. According to the shape of the crape myrtle tree, change the basin in time, remove all or part of the persistent soil, remove the surrounding soil and part of the rotten root, thick root, long root, over-dense root, plant the plant in the basin, add the culture soil to compaction, and pour enough water. The cultivated soil must be rich in organic matter, good drainage and air permeability and sufficient fertility to ensure that it blossoms and grows luxuriantly.

4. Reshaping and pruning: the pruning of crape myrtle bonsai should be re-pruned according to the need of bonsai shaping. In the growing season, pruning mainly removes dense branches, twigs that go around the tree shape, and branches that sprout at the base of the stem, all should be erased or cut off in time.

5. Removal of residual flowers: crape myrtle bonsai should blossom many times and bloom well within a year. After each flower shedding, the residual flowers should be removed in time to prevent fruit, promote the rapid expansion of secondary buds and blossom many times, but the flowering period is not neat enough. In addition, if there are not many secondary buds after the flower fade, each branch leaves 1 or 2 buds for re-pruning, usually budding in 14 days and full of flowers in about 35 days, which can make the branches of crape myrtle bonsai trees thicker and shorter (the average branch length is less than 15 cm), the tree shape is very compact, and the flowers are colorful and pleasing to the eye.

Disease and pest control of crape myrtle

1. Powdery mildew

[symptoms] powdery mildew mainly harms leaves, and young leaves are more likely to be infected than old leaves, and the disease also harms branches, shoots, flower buds and buds. In the early stage of the disease, small white powder spots appeared on the leaves, which were enlarged and showed round or irregular discolored patches. After the flowers were infected, the surface was covered with powdery layer, the spikes were deformed, and lost their ornamental value. The plants affected by powdery mildew will become short, the tender leaves are twisted, deformed and withered, the leaves do not develop, become smaller, the branches are deformed and so on, and the whole plant will die in serious cases.

[prevention and control] ① should strengthen fertilization and pay attention to drainage so as to avoid excessive humidity. Reduce the source of infection, combined with autumn and winter pruning, eliminate diseased branches and burn them centrally, and pay attention to timely removal of diseased buds, diseased leaves and diseased shoots during the growing season. When the disease occurs, the plant can be sprayed with 3000-fold solution of 25% verapamil wettable powder, 1000-fold solution of 70% methyl topiramate wettable powder, or 1000-fold solution of 80% Dysen zinc wettable powder.

2. Brown spot

[symptoms] crape myrtle brown spot mainly harms leaves. The disease spot on the leaf is round or nearly round, some are irregular, purple-brown to grayish brown, the edge color is lighter, not clear, there are gray-black mildew spots on both sides, when several disease spots appear on the leaf surface. The whole leaves turn yellow quickly and fall leaves ahead of time. High temperature, high humidity and frequent rainfall are beneficial to the occurrence of the disease.

[control] Autumn ploughing of crape myrtle garden or street crape myrtle, turning the surface fallen leaves into the deep soil to reduce the source of infection at the beginning of next year. Trim it in time to make it ventilated and transparent. Spray 1000 times of 50% carbendazim wettable powder or 75% chlorothalonil wettable powder in time at the initial stage of the disease.

3. APHIS gossypii

[symptoms] the harm of crape myrtle aphid to crape myrtle occurs year after year, and the back of tender leaves is often covered with pests. After damage, the new shoots are twisted, tender leaves curl, uneven, affect flower bud formation, and shorten inflorescences, even no flowers. At the same time, it will also induce coal fouling disease and spread virus disease.

[prevention and control] combined with pruning in winter, removing disease and insect branches, thin branches and over-dense branches can play a role in destroying some overwintering eggs. Family potted plants should also try to make the branches as bright and clean as possible, pay attention to clear the winged cortex of the branches, and concentrate on burning, so as to reduce the overwintering aphid eggs. Chemical control can spray 1500 times of 10% aphid lice net wettable powder, or 50% fenitrothion EC 1000 times, 40% omethoate EC 1000 times and 80% dichlorvos EC 1000 times, etc. at the same time, it can also control pests such as crape myrtle scale.

4. Velvet scale

[symptoms] the velvet scale sucks juice from female adults and nymphs in bud axils, leaves and branches, which often causes tree weakness and poor growth, and a large amount of honeydew secreted by it will induce serious coal fouling disease, which will cause leaves and twigs to be black and lose their ornamental value. it is one of the main pests harmful to crape myrtle.

[prevention and control] strengthen quarantine, prevent the flow of pathogens, apply fertilizer reasonably, enhance plant resistance to insects, maintain ventilation and light transmission, avoid excessive plant density, and burn insect branches in combination with pruning in winter and early spring. When the number of insects is small, manual scraping can be carried out. Spray 10-15 times turpentine mixture or 40-50 times engine oil emulsion 1-3 times in winter to eliminate overwintering female worms. before germination, spray 3-5 degree stone sulfur mixture or 3-5% diesel emulsion to kill overwintering nymphs.

5. Leaf wasp

[symptoms] Leaf wasps do harm to larvae, eat leaves, eat mesophyll, and eat up the tender leaves of the plant, leaving only a few main leaf veins, affecting plant photosynthesis, affecting the florescence of crape myrtle, reducing its ornamental value, and even leading to death.

[prevention and control] combine soil ploughing in winter and spring to eliminate overwintering cocoons. Look for spawning branch tips, leaves, artificial removal of egg tips, egg leaves or larvae that are still clustered after hatching. Bt was sprayed during the larval damage period. Emulsion 500x, 2.5% deltamethrin EC 3000 times, 20% fenvalerate 2000 times, 25% thiazuron 3 gel suspension 1500 times.

6. Spodoptera litura

[symptoms] the damage caused by the larvae is mainly caused by the larvae.

Physical control is mainly combined with pruning in winter to remove the overwintering cocoons on the branches so as to eliminate or reduce the source of insects. Pesticide control is best used before the larvae spread, spraying 1000 times of 80% dichlorvos EC and 2000 times of 2.5% deltamethrin EC.