The bracts of Prunus deltoides are large, colorful and lasting for a long time. The ornamental value of Bougainvillea is very high, and it is used for climbing flower cultivation in the south of China. Every Spring Festival, green leaves set off a bright red film, as if a peacock opened the screen, particularly bright. Northern potted plants, placed in the porch, courtyard and hall entrance, very eye-catching.
In the maintenance process of bougainvillea, improper maintenance methods will cause the yellow leaves to fall. What is the reason for the yellow leaves of Bougainvillea? The following small series will introduce the causes and solutions.
The leaves of Bougainvillea are yellowing. Let's first understand some living habits of Bougainvillea: 1. Bougainvillea likes warm and humid climate, not resistant to cold, high temperature, and afraid of dryness. It is safe to overwinter above 3 ℃ and bloom above 15 ℃.
2. There is plenty of light in bougainvillea. In the clay heavy loam with good drainage and rich minerals, it is resistant to barrenness, alkali, drought, ponding and repair.
3. The water requirement of deltoid flower is large, especially in midsummer, the water supply is insufficient, and it is easy to fall leaves, which directly affects the normal growth of plants or delay the flowering. If the soil is too wet, it will cause root rot. Tricornutum is an optically active plant, such as insufficient light or too shade, weak growth of new branches and dim leaves. Cause analysis and solution for yellowing of Bougainvillea leaves 1. Improper watering
The amount of watering varies from season to season. The water demand of Bougainvillea is relatively large. It should be watered once a day in spring and autumn, and once in the morning and evening in summer. The temperature is low in winter and the plant is in dormant state. Therefore, watering should be controlled to keep the soil moist.
2. Improper lighting
Bougainvillea is a kind of positive flower because it likes light. In growing season, insufficient light will lead to weak growth of the plant, which will affect the pregnant bud and flowering. Therefore, the seedlings that are newly planted in the pot should be placed in the semi shade place all the year round. In winter, it should be placed in front of the south facing window, and the lighting time should not be less than 8 hours, otherwise a large number of leaves are easy to appear.
3. Improper soil selection (ponding) Bougainvillea has no strict requirements on soil, but it is afraid of ponding and is not resistant to waterlogging. Therefore, it is necessary to select loose and well drained culture soil. Generally, 4 parts of humus soil, 4 parts of garden soil and 2 parts of sand can be selected as cultivation soil, and sun dried pond mud mixed with some coal cake residue can be used as basin soil.
4. Improper fertilization
In summer and winter, fertilizer should be stopped because of slow growth or dormancy, so as to avoid fertilizer damage. Do not apply thick fertilizer or raw fertilizer (not fully decomposed organic fertilizer) to prevent root injury, resulting in leaf charring off and even death of the whole plant.
5. Leaf spot
At first, the lesions were yellowish brown, surrounded by yellowish green halos, and then expanded into nearly round or irregular lesions with dark brown edges. In the later stage, black particles appeared on the lesions. In the early stage of the disease, 50% carbendazim WP 500 times solution can be used for prevention and control, once every 7-10 days. In severe cases, according to the actual experience, spray once again on the fourth day, and then spray once every seven days. 3-4 times in succession, the control effect is good.
6. Brown spot
Brown spot disease is characterized by damaged leaves, which produce yellowish brown to light brown spots with a diameter of 0.1-0.5cm.
The control methods of brown spot disease were as follows
1. Let the plant ventilate and transmit light;
2. Attention should be paid to increase or maintain the humidity of leaves;
3. In case of infection, the diseased branches and leaves should be cut off in time and destroyed;
4. In the early stage of infection, spraying 1000 times of 50% abamectin solution or other fungicides can inhibit the development of the disease.