Detailed Explanation of Large-Scale Cultivation Techniques for Belgian Azaleas

Although the Belgian azalea was introduced from Europe, it has a strong Chinese "bloodline." From 1838 to 1939, Robert Fortune and other British and American botanists came to our country several times, bringing early-flowering azalea varieties such as the Jiangnan azalea into Europe, where they were crossed with East Asian azaleas, peony azaleas, hairy white azaleas and other varieties, producing many excellent cultivar groups. Because the breeding center at that time was located in Ghent, Belgium, this azalea group is customarily called "Belgian azalea." After being introduced into our country, it was also called "Western azalea." The Belgian azalea plant is relatively short and small, with flowers resembling peonies, mostly semi-double or double, and some cultivars even have ruffled edges. The petals come in many colors, including bright red, peach red, water red, orange red, pure white, milky white and red-and-white mixtures. Many plants have more than two flower colors, presenting a thousand appearances and delicate elegance. The most remarkable thing is that it can bloom in all four seasons, with the flowering period lasting about 60 d, and the flowering period can be manually regulated, so it is deeply favored by people in various places. In 1999, Nanyang Village, Hetang Town, Gutian County, took the lead in building the largest Belgian azalea production base in eastern Fujian, with an annual output of more than 50,000 pots, sold far away to Beijing, Guangzhou and other cities. The successful experience of its large-scale cultivation is investigated and summarized as follows:

1 Cutting propagation

11 Cutting period

Cuttings can be taken in all four seasons, but the survival rate is highest in April to May and September to October.

12 Seedbed preparation

Choose loose-textured, well-drained sandy loam soil, and make beds in fields free of pests and diseases (surface width 12 m, height 03 m). After leveling the bed surface, spread a layer of fresh loess 3 cm thick on top, apply an appropriate amount of clear water, press slightly flat, and then the seedlings can be inserted.

13 Preparation of cuttings

Select current-year, semi-lignified, pest- and disease-free, robustly growing branches and cut them into cuttings, each 3-5 cm long. Remove the terminal bud and 1-2 leaves at the base, keep 3-4 leaves on the upper part, and prepare for cutting.

14 Cutting method

First soak the end of the cutting that goes into the soil in a 1% rooting agent solution for a few seconds, then insert it into the seedbed. The cutting density should be such that the leaves of each cutting can spread out naturally, with 3-4 cm between front, back, left and right, and the insertion depth is 2 cm. After insertion, water thoroughly with clear water again. Arch bamboo strips over the seedbed, cover tightly with transparent plastic film, and then cover the film with a 60% shade net to control the seedbed temperature and avoid strong sunlight exposure, which helps survival.

15 Management after cutting

At a normal temperature of 12-28°C, roots and new leaves grow about 20 d after cutting. Do not fertilize, and do not water when the soil is moist. After 35 d, the film can be gradually removed, leaving only the shade net for hardening the seedlings. After 50 d, they can be transplanted into pots or temporarily planted elsewhere. Two d before transplanting, spray once with a 015% Topsin and 01% ternary compound fertilizer solution to strengthen the seedlings and prevent disease.

2 Transplanting and maintenance

21 Temporary planting and final planting

First move the rooted seedlings from cuttings to field beds for temporary planting. When the seedlings grow to about 10 cm high, plant them in 13 cm x 13 cm plastic nutrient cups (simple black recycled plastic pots) for cultivation; alternatively, first move the rooted seedlings from cuttings into small 10 cm x 10 cm nutrient cups for 40 d. After the root system fills the nutrient cup, transplant them into 13 cm x 13 cm nutrient cups or larger flower pots for cultivation, until flower buds appear, when they can be shipped out in batches @#@136@#@. The ingredients in the nutrient cups can be coconut coir and peat soil (1:5) or tung oil cake powder and peat soil (1:10), mixed evenly, stacked and fully composted to make nutrient soil.

22 Maintenance management

221 Scientific water management Watering is a routine maintenance task. The roots of Western azaleas are extremely fine, fearing both waterlogging and drought, so watering should be done timely and appropriately according to the season, weather and needs at different growth stages. Generally, in winter and the plum rain season on sunny days or at the seedling stage, water an appropriate amount every 3-5 d when the soil is relatively dry, keeping the soil moist; in spring on sunny days or under greenhouse cultivation, water an appropriate amount every 2-3 d; in autumn on dry sunny days or during flowering, water every evening; in summer during high temperature and heat or the peak flowering period, water once each morning and evening. Watering should use clear water or tap water that has been left standing for more than one day. Do not overwater, to avoid water accumulation and root rot.

222 Rational fertilization Fertilizer should be applied according to the seedlings. At the seedling stage, apply 01%-02% multi-element foliar fertilizer solution for about 20 d. Starting one month before flowering, the amount of fertilizer should be appropriately increased, mainly 02% quick-acting phosphorus and potassium fertilizer, applied once every 10 d, to prevent excessive vegetative growth and promote more and larger flowers with bright colors. Stop fertilizing during the flowering period to avoid promoting new shoots and harming flowering. Note that fertilization should not be too concentrated or excessive, to avoid fertilizer damage. Western azaleas also often suffer from chlorosis due to iron deficiency. If this disease occurs, spray the whole plant with 02% ferrous sulfate solution in time for prevention and control.

223 Shading and heat prevention Western azaleas are suitable for growing in a mild, cool and moist environment, and avoid direct sunlight exposure, high temperature, dryness and muggy weather. Therefore, the cultivation site should be chosen in a south-facing, ventilated, semi-shaded place or one with scattered sunlight, and can also be covered with a 60% shade net. Especially in summer, ventilation, moisture, sun protection and heat prevention should be ensured.

224 Crown shaping and flowering period control Crown pruning and shaping should be carried out in combination with cutting cuttings and flowering period control. Pruning and shaping means arranging the crown into a mushroom shape through branch pruning, bud removal, flower bud thinning and shape support, and cutting the branches suitable for cuttings into cuttings for timely propagation. At normal temperature, the Belgian azalea needs 180 d from transplanted rooted seedling to flowering. After the flowers fade or after artificially removing the flower buds, it also takes 180 d to bloom again. By repeating this operation, decide whether to remove or keep flower buds according to different market times, so as to control the flowering period. For batch trafficking, package and transport for market 20-30 d before flowering. If it is decided to market for National Day, then the flower buds and flowers must be removed at the end of March, and the whole tree can bloom simultaneously by the end of September.

225 Pest and disease control The main diseases of Belgian azaleas include flower rot, brown spot, black stem disease and anthracnose; the main insect pests include azalea lace bug, short-haired mite and aphids. For disease prevention, spray 70% Topsin 1000-fold solution or 62% Xiansheng mixed powder 1000-fold solution once every 7 d, for 3 consecutive sprays, which can effectively control diseases; for insect control, in early to mid-April each year when young insects are abundant, spray 18% Aifuding 2000-fold solution 1-2 times, which can basically eliminate the pests without polluting the environment.