Detailed Explanation of Redbud Tree Planting Methods and Technical Key Points
Redbud, commonly known as Mantiaohong, belongs to the Fabaceae family, Cercis genus, and is a deciduous tree or shrub native to China. It is distributed in provinces including Hebei, Shaanxi, Henan, Gansu, Guangdong, Yunnan, Sichuan, western Hubei, and southern Liaoning. Its growth management is relatively extensive, and it has high medicinal and ornamental value. It prefers sunlight and has a certain degree of cold tolerance. It can grow in fertile, well-drained soil. Production areas include Jiangsu, Shandong, Henan, Beijing, Anhui, and other places.
Cultivation Techniques
Water and Fertilizer Management
Redbud prefers a moist environment. After planting, it should be watered immediately with the first watering, the second watering on the third day, and the third watering after the sixth day. After the third watering, water according to weather conditions, keeping the soil moist but not waterlogged. Water promptly in summer, and spray the leaves with water; drain promptly after rain to prevent root rot from excess water. After autumn begins, if temperatures are not high, watering should be controlled to prevent autumn growth. Before winter, water sufficiently with antifreeze water. In early March of the following year, water with green-up water. Except for July and August, when watering depends on precipitation, water thoroughly once each month from April to October, and water with antifreeze water before winter. In the third year, use the same watering method; in the fourth year, enter normal management, but antifreeze water and green-up water should be applied sufficiently and thoroughly. If conditions permit, water thoroughly once in mid-to-late April and once in late September; in other seasons, it can rely on natural rainfall. Some people believe that redbud is drought-tolerant and afraid of flooding, but in fact redbud prefers a moist environment; it simply cannot grow in waterlogged conditions.
Redbud prefers fertilizer. With sufficient fertilizer, branches are luxuriant and leaves are abundant, with many flowers and vivid colors; with insufficient fertilizer, branches are sparse and leaves are few, with few flowers and pale colors. Base fertilizer should be applied sufficiently at planting time, preferably leaf mold, barnyard manure, or dried chicken manure, thoroughly mixed with the planting soil before use, otherwise the roots will be burned. After entering normal management, apply a nitrogen fertilizer once each year after flowering to promote vigorous growth, and apply a phosphorus-potassium compound fertilizer once in early autumn to benefit flower bud differentiation and safe overwintering after new branches lignify. In early winter, combine with watering antifreeze water and apply cow or horse manure. If plants grow poorly, foliar spray with 0.2% potassium dihydrogen phosphate solution and 0.5% urea solution.
Shaping and Pruning
Redbud is often used as a shrub in landscaping, so pruning should be strengthened from the seedling nurturing stage to help form a good plant shape.
After transplanting, seedlings can be lightly cut back to encourage more branching, expand the nutrient area, accumulate nutrients, and develop the root system. In the following spring, they can be heavily cut back to stimulate new shoots; select 3 well-growing branches to keep and remove all the rest. During the growing season, strengthen water and fertilizer management and pinch the retained branches. After planting, remove excess root suckers promptly, strengthen the nurturing of branches retained from the previous year, and pinch frequently to encourage more secondary branches.
During cultivation, renewal of flowering branches should be strengthened. Practice has proven that old branches over 5 years old bear fewer flowers, and the flower buds move upward, affecting ornamental value, so they should be renewed promptly.
Pest and Disease Control
Control Measures for Major Insect Pests
Insect pests include Anoplocnemis binotata, cotton aphid, Clania variegata, Parasa lepida, Latoia lepida, and Narosa nigrisigna. If they occur, during the nymph stage of Anoplocnemis binotata, spray 48% chlorpyrifos EC at 3500 times dilution or 25% chlorfenapyr suspension concentrate at 1000 times dilution for control; if cotton aphid occurs, spray lime sulfur mixture in early spring; if Clania variegata occurs, when the newly hatched larvae have not yet formed their protective bags, spray 20% diflubenzuron suspension concentrate at 7000 times dilution for control; if Parasa lepida, Latoia lepida, or Narosa nigrisigna occur, during their larval stage use Bt emulsion at 500 times dilution, or 25% fenoxycarb wettable powder at 300 times dilution, or 1.2% matrine EC at 1000 times dilution for control.
Control Measures for Major Diseases
The main diseases are redbud angular leaf spot, redbud twig blight, and redbud sooty mold. Redbud angular leaf spot infects redbud leaves. In the early stage, brown spots appear on the leaves; as the disease develops, the spots gradually expand to form irregular angular patches, and in the late stage, dark green powdery granules form on the lesions.
This disease is caused by infection by the deuteromycete fungus Pseudocercospora cercidicola. The pathogen overwinters as mycelium on diseased branches and fallen leaves. In the following spring, conidia spread through wind and rain and invade through stomata or wounds. The rainy season is the peak period of the disease; large-scale outbreaks often cause leaves to wither and drop early.
Control methods include reasonable pruning and attention to ventilation and light penetration; strengthening water and fertilizer management, paying attention to nutritional balance, and not applying excessive nitrogen fertilizer; spraying 75% Dacotech wettable granules at 800 times dilution for control, once every seven days, for three to four consecutive sprays.
Redbud twig blight mainly harms redbud branches. In the early stage, small canker spots appear on the branches; then the canker spots expand, the diseased area becomes sunken, the center of the lesion is black, the edges crack, the xylem of the lesion turns brown-black, and when the lesion expands around the branch stem in a full circle, the branches and leaves above the diseased area wither.
This disease is caused by infection by the deuteromycete fungus Botryosphaeria dothidea. The pathogen overwinters as mycelium on branch canker spots and begins infecting in spring when humidity and temperature are suitable.
Control methods include promptly pruning and burning diseased branches; for canker lesions on large branches and stems, scrape off the lesion and apply sulfur powder paste to the wound, or mix 50 g of 50% tebuconazole with 250 g of 50% sulfur suspension concentrate and apply; during the disease season, spray 75% chlorothalonil wettable granules at 700 times dilution, once every 10 days, for three to four consecutive sprays.
Redbud sooty mold mainly harms leaves. In the early stage, dotted and patchy soot layers appear on the leaves; the dots and patches gradually enlarge and thicken, connecting with each other, and in severe cases can cover the entire leaf.
This disease is caused by infection by sooty mold fungi in the Deuteromycotina. The pathogen overwinters as mycelium on diseased leaves and branches and is spread by aphids, scale insects, and wind and rain. In June, when scale insects and aphids occur in large numbers, their excrement and plant exudates serve as nutrients, inducing massive reproduction of the pathogen.
During control, promptly kill aphids and scale insects; strengthen pruning and maintain ventilation and light penetration; for minor occurrences, wipe clean with a clean cloth.