Cultivation techniques of fast-growing Lagerstroemia speciosa

First, the planting density of Lagerstroemia indica should be carried out after autumn leaves fall and before spring buds germinate. Small seedlings can be transplanted with bare roots, and large seedlings need soil balls to transplant; Should choose fertile, well-drained calcareous soil and sandy loam for planting. Fine soil preparation and sufficient base fertilizer should be applied. In the short term, the plant spacing should be 0.65 * 1m, that is, per mu 1000 plants. The medium-term planting distance can be 1.6X2, and 200 plants can be planted per mu. Dormancy is the best time for seedling transplantation. After transplanting, root water should be poured in time, and ditch cleaning and soil cultivation should be done well. Daily management mainly includes loosening soil, weeding, water and fertilizer and pest control. The second is water and fertilizer management, which should always keep the soil moist throughout the growing season, and water it for 10 days in spring drought; It is not advisable to water too much in autumn flowering period, generally 15 days or so 1 time; Pour enough antifreeze in winter. Lagerstroemia indica fertilization is generally in winter or early spring; Each plant can be applied with decomposed human manure 10 ~ 15 kg or organic fertilizer 2 ~ 4 kg, and a small amount of inorganic fertilizer can be applied in May ~ June. In the seedling growing season, nitrogen fertilizer and compound fertilizer should be applied to promote seedling growth. In the first three years after planting, 65,438+00 ~ 65,438+05 kg (mainly organic fertilizers such as compost and cake fertilizer) should be applied to the roots every winter or spring before germination, and some compound fertilizers can also be applied as appropriate. The surviving Lagerstroemia indica is watered 1 time every spring, 3 ~ 4 times later and 1 ~ 2 times in flowering period. Water frozen water once before freezing in North China, and pay attention to drainage after rain. Third, soil management should pay attention to the weather changes in summer and autumn, and do a good job in drought prevention, drainage and waterlogging reduction in time. Fourth, the plastic pruning of Lagerstroemia speciosa is mainly in dormant period, supplemented by growing period, and different pruning methods are adopted according to different garden environments. 1. A naturally happy shape. After planting Lagerstroemia indica, when Lagerstroemia indica grows to a certain height, the core is to promote secondary branching, and then 3-5 robust branches are selected as main branches, and 1-2 branches with different angles and balanced growth are selected as side branches. When pruning every year, the upper branches with larger angles should be selected as extension branches and pruned appropriately. This kind of tree has good permeability and can blossom in three dimensions. 2. The trunk is layered. This tree needs obvious trunk and main branches. The trunk is layered and the main branches are evenly distributed on the trunk. Generally, there are about 4 main branches, and 2 left and right side branches are left on the main branch. This tree shape is suitable for garden cultivation and solitary tree planting. 3. Control flowering and pruning. In order to make Lagerstroemia indica bloom in the "Eleventh", the new shoots of Lagerstroemia indica in full bloom can be cut short in early August, and all the branches and leaves at the tip of the flower branches can be cut off by about 1/3. After that, strengthen the management of water and fertilizer, apply fertilizer for 2 ~ 3 times, and flower buds can form again on the new shoots in about 30 days. Generally, it can bloom again in about 50 days from the date of cutting short, adding a festive atmosphere to the festival. Five, pest control mainly includes aphids, crape myrtle, giant salamander and pest-induced sooty blotch, which should be prevented in time. 1. For aphids, 800 ~ 1000 times of 1.2% Kuyan EC, 3000 times of 50% pirimicarb, 2500 ~ 3000 times of 2.5% triadimefon or 3000 ~ 4000 times of 6% can be sprayed. 2. For Lagerstroemia indica, if the wax does not form or just begins to form a wax layer within 7 days after the incubation period, spray1500 ~ 2,000 times of 40% quick-killing EC, 2,000 times of 6% imidacloprid soluble concentrated solution and 2,500 times of pyrethroid pesticides on the branches and leaves. The above three chemicals are used alternately and sprayed once every 7 ~ 10 day for 2 ~ 3 times in a row, which can achieve good results. The key to spraying is to seize the opportunity (nymph stage). Once the shell is formed, spraying is difficult to be effective. 3. For the giant salamander, the pouch of the marsupial moth on the tree can be seen after defoliation in winter, which is artificially removed; Trapping and killing adults with frequency vibration insecticidal lamp; Moth larvae are sensitive to trichlorfon, and good results can be achieved by using 90% trichlorfon crystal 1000 to 1500 times. You can also use 3,500 ~ 4,000 times of 2.5% deltamethrin EC, or 1, 000 ~ 1, 500 times of 50% phoxim EC and 1, 500 times of 20% pyrethroid EC to spray evenly and thoughtfully. 4. For sooty blotch, it is mainly due to aphids and scale insects.