Forsythia Propagation and Cultivation Techniques and Pest and Disease Control Measures

Forsythia is an economic shrub crop. It has strong cold resistance and likes sunlight. It can grow in both poor and fertile land and has strong adaptability. It can serve not only as an ornamental plant but also as a traditional Chinese medicine, used for reducing inflammation and detoxifying. Let's take a look at the seedling raising and cultivation techniques for forsythia.

1. Seedling Raising

Forsythia has strong sprouting ability and is not strict about soil requirements. Because it likes light, wild forsythia generally grows on sunny slopes or semi-shaded and semi-sunny slopes. There are several methods of forsythia seedling raising, including sowing, division, cuttings, layering, etc. At present, sowing-based seedling raising is the main method.

1.1 Plot Selection

Although forsythia is not strict about the soil it grows in, when raising seedlings, flat and fertile soil should be selected. The soil should have good drainage and irrigation conditions, because too much sandy soil will cause poor seedling growth. After the plot is selected, land preparation should be carried out. Land preparation is done in autumn, and organic fertilizer should be applied along with it, followed by deep plowing to remove weeds and debris.

1.2 Seed Collection

After forsythia matures in autumn, harvesting is carried out before the autumn frost. Harvesting mainly targets yellow, bright, cracked fruits. The fruits are beaten to obtain seeds. Then seeds that are plump, healthy, and free of pests and diseases are selected from mother trees. After selection, the seeds are stored in a cool place for seedling raising.

1.3 Seed Treatment

Forsythia seeds have dormancy, so seed treatment is needed in spring. Before germination promotion, the seeds are generally soaked in a solution of gibberellin and alcohol to wake the dormant seeds. In March, the seeds are germinated by soaking the selected seeds in warm water for about 3 hours, then removing them and draining the water, placing them in sand in a

north wind and sunny spot. Note to turn them every day. When about one third of the seeds have cracked open, they can be sown.

1.4 Sowing

After forsythia seeds germinate, furrows should be opened in the sowing plot before sowing, then fine sand and seeds are scattered into the furrows together. After covering with soil, press it firm and cover with straw curtains to prevent drying. After covering with soil, spray herbicide to kill young weeds, but do not water within 10 hours after sowing. When the seedlings grow to about 5cm, thin them to establish the stand, selecting large and strong seedlings, and combine this with weeding and watering, keeping the spacing between seedling plants at about 5cm as the optimum. One month after planting, apply fertilizer and weed while watering. When the seedlings reach 15cm, thin them and strengthen field management and weed control.

1.5 Transplanting

After seedling raising, forsythia is generally transplanted in the spring of the second year. If forsythia is planted in patches, when the seeds mature in autumn and fall naturally, many small seedlings will grow. When the number of seedlings needed is not large, this natural seedling method can be used. When transplanting, the seedlings should be dug out together with the root soil. Before planting, dig planting holes with a diameter of about 30cm, with a distance of about 150cm between planting holes. Put 5kg of compound fertilizer into each planting hole, and transplant the forsythia seedlings into the holes. Then fill with soil. When half filled, lift the seedling upward a little to promote the spreading of the root system, then fill the soil full and tread it firm. If the soil after transplanting is relatively dry, water it promptly.

1.6 Cutting Propagation

Forsythia cutting propagation is generally carried out in summer, and rainy days are best. When taking cuttings, select healthy, pest-free, lignified branches about 3 years old, cut them into cuttings about 20cm long, keeping about 3 buds and 2 leaves on each cutting to help the cutting absorb water and carry out photosynthesis. After the cuttings are prepared, cut the lower end at a slant to help rooting. Tie 50 cuttings into a bundle, soak them in rooting powder solution, take them out and let them cool, then insert them into the soil, cover with soil and press firm. What cutting propagation requires attention to is the suitable temperature; about 13°C is most suitable, but it must not be higher than 27°C. Although forsythia has strong growth ability, when the bark area roots or adventitious buds root, mixed tree types may grow. If light is not timely, it will affect the growth cycle of forsythia roots and reduce the rooting rate. Therefore, after cutting propagation, temperature and light must be well controlled. If the sunlight is strong, shading can be carried out after forsythia cuttings are inserted, but the light transmittance of the shade net should be about 60. After the forsythia cuttings have grown roots, the shade net can be removed. Generally, shading is needed from 10 a.m. to 4 p.m. every day. Forsythia cuttings are generally taken in environments with high temperature and humidity. After cutting, infection and rot easily occur, so carbendazim is needed for disinfection to prevent mold from forming before the forsythia wounds heal. After the forsythia cutting wounds heal, foliar urea fertilization is needed about once every 7 days. After rooting, a mixed solution of urea and potassium dihydrogen phosphate should be sprayed to promote healthy root growth and increase the lignification degree of the seedlings.

1.7 Layering Propagation

Forsythia layering propagation can generally be carried out in spring and autumn. In spring, longer forsythia branches should be selected, bent down and buried directly in the soil, then watered to keep the soil moist. Generally, the branches can root 60 days after layering. In autumn, the front end of the branch needs to be cut off, and after temporary planting, layering and field planting are carried out in the spring of the second year.

1.8 Division Propagation

Forsythia division propagation is generally carried out from after leaf fall in autumn to before leaf development in spring. During division propagation, the forsythia plant can be dug out with one branch above ground and roots below ground. After field planting, new plants sprouting around mother plants more than 4 years old need to be dug out separately for field planting.

1.9 Field Management

During the forsythia seedling period, when the seedlings reach 20cm, weeding, loosening the soil, and fertilizing can be carried out. When thinning, leave 2 plants per hole, and water in a timely manner. When the seedlings reach about 30cm, farmyard manure should be applied to promote seedling growth. When the seedlings reach 70cm, the top shoot should be cut off to promote side branch development and cultivate the side branches into main branches. After forsythia has grown, pruning should be carried out to promote ventilation and light penetration, and to promote early fruiting and early fruit ripening.

2. Cultivation Techniques

2.1 Plot Selection

The plot for cultivating forsythia should be prepared in advance. Generally, gently sloping hilly plots are selected, and land preparation is carried out using strip spacing of 3m and length of 70cm. After transplanting, raw soil or stone flakes should be used as the backfill ridge, and mature soil should be used for backfilling, making the ridge 25cm high, 30cm wide, and 30cm thick.

2.2 Transplanting

Forsythia transplanting is generally carried out between autumn and spring, after leaf fall. In order to improve the survival rate of transplanting, the forsythia can first be cut back, and then before transplanting, the soil-covered roots of the forsythia should be dipped in rooting powder or mixed with mud slurry. After transplanting, the soil layer should be treaded firm and compacted in layers so that the seedling root system is straight and easy to grow and spread.

2.3 Tending Management

2.3.1 Intertillage and Weeding After forsythia transplanting, loosening the soil and weeding should be carried out once every winter, combined with fertilization, mainly using cake fertilizer and farmyard manure. During the growth period, forsythia seedlings can be intercropped and treated with low stalks in the early stage, combined with watering and fertilization.

2.3.2 Reasonable Fertilization Fertilization should be carried out 3 years after forsythia field planting. This fertilization is mainly urea, with the amount controlled at 225kg per mu; fertilization should also be carried out 5 years after field planting. This fertilization is mainly a mixture of nitrogen fertilizer, phosphate fertilizer, and potassium fertilizer, with the amount controlled at 600kg per mu.

2.3.3 Irrigation and Drainage After forsythia transplanting, watering should be carried out during dry periods. If the irrigation conditions of the plot are poor, soil moisture conservation work should be carried out. After forsythia transplanting, if it is the rainy season, drainage treatment should be carried out by digging drainage ditches to remove accumulated water.

2.3.4 Shaping and Pruning In the first winter after forsythia transplanting, after the leaves have completely fallen, pruning should be carried out at about 70cm from the ground on the main branches. In the second summer, pinching should be carried out to promote the development of forsythia side branches. After pruning, about 4 strong branches should be kept on the main branches for cultivating secondary main branches. After forsythia grows for several years, pruning and shaping can basically form a shape that is round outside and hollow inside with good light transmission. This tree shape is suitable for forsythia photosynthesis and is beneficial to nutrient absorption. After that, dead branches should be pruned every winter, and crossing branches and diseased branches should be cut off. Aging, perennial, and fruiting branch groups should be shortened to promote the main trunk to produce new strong branches, restore forsythia growth, and increase the fruiting rate.

2.4 Pest and Disease Control

The main pest and disease during forsythia growth is leaf spot disease, which is caused by fungal infection. When severe, the entire leaf will wither and die. High temperature and a closed environment are the main reasons for the occurrence of leaf spot disease. Leaf spot disease generally occurs in late May, with about July as the peak period. The main control measures are to prune diseased branches in a timely manner and prune overly dense branches so that forsythia has good light transmission. At the same time, strengthen fertilizer and water management, pay attention to the application of nitrogen fertilizer, and keep nutrition balanced during forsythia growth. After May, during the period when leaf spot disease is prone to occur, the main trunk can be whitewashed in advance for prevention. The main insect pest during forsythia growth is the mole cricket. Mole crickets must be controlled during the forsythia seedling stage and emergence stage; poor control will affect the seedling survival rate. When mole crickets occur, they mainly gnaw the tender stems and rhizomes of forsythia. In severe cases, they cause seedling death and can create gaps in the rows. Another insect pest is the stem borer. The stem borer mainly bores into the woody part of the forsythia main trunk and damages the pith, and in severe cases can cause forsythia to be unable to bloom and bear fruit.

2.5 Harvesting

Forsythia is divided into green forsythia and yellow forsythia. The green fruits harvested in September are generally green forsythia, while the yellow fruits harvested after October are generally yellow forsythia. After harvesting, the processing of forsythia should be protected from rain to avoid quality reduction.

3. Conclusion

Scientific and reasonable design is needed when raising seedlings and planting forsythia, with ventilation and light, and reasonable fertilization and irrigation, to ensure a high survival rate of forsythia at the seedling stage, good growth after transplanting, and freedom from pest and disease damage.

Standardized Cultivation Techniques for Forsythia

Forsythia, a deciduous shrub, is a plant of the genus Forsythia in the Oleaceae family. It has antibacterial, anti-inflammatory, antipyretic, antiemetic, diuretic and cardiotonic, anti-liver damage, and analgesic effects.

I. Characteristics and Traits

Forsythia can reach 3 meters in height. The branches spread out or droop, the branchlets are slightly 4-angled, the internodes are hollow, and there are obvious lenticels. The simple leaves are opposite or divided into 3 leaflets. The leaf blades are ovate, with irregular serrations at the edges, green on the surface, and semi-leathery. The flowers open before the leaves, one to several flowers, axillary, yellow. The capsule is narrowly ovate, slightly flattened, with a tip like a bird's beak, and splits into two valves when ripe. The seeds are narrowly elliptical, brown, with a thin wing on one side. The flowering period is March-April, and the fruit ripening period is August-October.

Forsythia is cold-resistant, drought-resistant, and barren-resistant. It has low requirements for climate and soil and has a wide suitable range. It can grow on dry sunny slopes or in soil-containing rock crevices, and even on weathered parent material of bedrock or purple sandstone and shale. Forsythia has a developed root system. Although the main root is not very prominent, its lateral roots are relatively thick and long, and there are many fibrous roots spreading widely around the main root, greatly enhancing its ability to absorb nutrients and stabilize soil. Forsythia has strong cold resistance. After cold hardening, it can tolerate a low temperature of -50°C. Its amazing cold resistance makes it an outstanding choice for northern garden landscaping. Forsythia has strong sprouting ability and rapid clump formation, and can quickly expand its distribution range.

II. Cultivation Techniques

1. Site selection, land preparation, and fertilization. For artificial cultivation of forsythia, a plot with sufficient sunlight, loose and fertile soil, high humus content, shelter from wind, and sandy loam soil should be selected for planting. Apply 2000 kg of farmyard manure per mu. Use the wide-ridge high-bed technique, with a bed width of 130-140 cm, length determined as needed, bed height of 10-12 cm, and bed spacing of 30 cm.

2. Propagation techniques. Forsythia is relatively easy to survive, and cultivation and management techniques are simple. It can be propagated by sowing seedlings, cuttings, division, and layering. (1) Seed propagation. Sow seeds in mid-to-late May, seedlings emerge in about half a month. When the seedlings are 7-10 cm tall, carry out the first thinning, removing part of the overly dense weak seedlings. When the seedlings are 13-17 cm tall, carry out the second thinning, leaving 1 seedling every 7-10 cm. After that, carry out intertillage, weeding, and topdressing management in a timely manner. After one year of cultivation, when the seedlings are more than 33 cm tall, they can be field planted. (2) Division propagation. From after leaf fall in winter to before bud break in early spring, some seedlings growing in clumps around the mother plant can be dug out and planted. Soil can also be banked around the base of the mother plant to encourage the seedlings to grow more roots, which helps survival and growth after planting. (3) Layering propagation. In spring, bend the drooping branches of the plant and bury them in the soil. In the following spring, cut them from the mother plant and field plant them. (4) Cutting propagation. Select healthy young branches 1-2 years old and cut them into cuttings 30-40 cm long. In late April of spring, in a prepared bed, according to the base planting requirements, plant with a row spacing of 50 cm and plant spacing of 40 cm, planting 1 strong seedling per hole. Cover with soil and press firm, water thoroughly to settle the roots, then cover with soil slightly higher than the ground in a mound shape.

3. Field management. (1) Intertillage and weeding. Carry out intertillage and weeding once every winter beside the forsythia trees. Weeds around the plants can be cut or pulled by hand. (2) Fertilization. Apply an appropriate amount of compost and stable manure as topdressing, opening furrows beside the plants, applying, and then covering with soil. (3) Drainage and irrigation. Pay attention to keeping the soil moist. Water in time during drought, and open ditches for drainage during the rainy season to avoid root rot from accumulated water.

III. Harvesting and Processing

Forsythia blooms and bears fruit 3-4 years after field planting. Generally, after the frost, the fruit is harvested when it changes from green to earthy yellow and is about to crack. The yield is 40-50 kg of fruit per mu.

Characteristics and traits: The leaf sheath of the seedling is purple. The mature plant type is semi-compact, with a plant height of 300 cm, ear height of 116 cm, and 20-21 leaves on the whole plant. The growth period is about 119 days. The tassel has 10-15 branches, the anthers are light purple, and the silks are light green. The ear is cylindrical, the cob is white, the ear length is 21.0 cm, the number of ear rows is 16, and the bald tip is 0.6 cm. The kernels are yellow, semi-dent-shaped, with a 1000-kernel weight of 401.9 grams and a kernel yield of 84.9%. According to the determination by the Grain Quality Supervision, Inspection and Testing Center of the Ministry of Agriculture in 2013, crude protein (dry basis) was 9.70%, crude fat (dry basis) was 4.65%, crude starch (dry basis) was 73.06%, and lysine (dry basis) was 0.31%.

Disease resistance identification: Identified by the Institute of Plant Protection, Jilin Academy of Agricultural Sciences. In 2012, it was highly resistant to head smut, resistant to stalk rot, and susceptible to northern leaf blight, curvularia leaf spot, and corn borer; in 2013, it was highly resistant to head smut, moderately resistant to stalk rot, and susceptible to northern leaf blight, curvularia leaf spot, and corn borer.

Yield performance: In the 2012 spring sowing group regional trial in the Taihang Mountain area of Hebei Province, the average yield per mu was 781.6 kg. In the 2013 regional trial of the same group, the average yield per mu was 749.3 kg. In the 2013 production trial, the average yield per mu was 717.0 kg.

Cultivation points: Sow at the right time to ensure full stand. The suitable density is 3500 plants per mu. Apply 15 kg of diammonium phosphate per mu as seed fertilizer, and at the 12-13 visible leaf stage, apply 35 kg of urea per mu as topdressing. Do a good job in pest and disease control. Pay attention to controlling corn borer.

Cultivation and Management Techniques for Forsythia

Forsythia is also known as Huangshoudan, Huanghuagan, Huangshoudai, and Shoudaidan, and is classified in the genus Forsythia of the Oleaceae family. It is produced in the northern, central, and northeastern provinces of China, and is now cultivated in many places. In spring, forsythia blooms all over the tree, and the golden branches sway with the spring breeze in a very natural and graceful way. It is an important early-spring flowering shrub. Its key planting points are introduced below for reference only.

I. Morphological Characteristics and Biological Traits

Forsythia is a deciduous shrub, up to 3 m tall, with clustered, upright stems, spreading branches, and arching drooping branches; the branchlets are yellowish brown, slightly 4-angled, with obvious white lenticels, and hollow pith. The simple leaves or 3 leaflets are opposite. The leaves are ovate to elliptic-ovate, 4-9 cm long, hairless, with a sharply pointed tip, rounded to broadly wedge-shaped base, and coarse serrations along the leaf margin. Flowers open before leaves, usually solitary, rarely 3 in axils; calyx lobes 4, oblong; corolla golden yellow, lobes 4, obovate-elliptic; stamens 2; there are two types of flowers, one with stamens longer than the pistil and one with the pistil longer than the stamens, and the two types do not grow on the same plant. The flowering period is April-May. The capsule is ovate, 2-loculed, and the seeds are winged. The fruiting period is June-September.

Forsythia likes light but has some shade tolerance and can grow normally in open woodland, but the number of flowers is not as great as in places with sufficient light; forsythia is cold-resistant and can overwinter safely in the northeastern provinces; it likes moisture, tolerates drought, and fears waterlogging. It grows best in moist soil, but should not be planted in low-lying areas, as accumulated water can easily cause root rot and plant death; it has low soil requirements and can grow normally in loam, plain sandy soil, and light clay, but grows best in sandy loam and plain sandy soil; it has some saline-alkali tolerance and grows well in saline-alkali soil with pH08.8 and a salt content of 0.2%.

II. Water and Fertilizer Management

Forsythia is drought-resistant but likes a moist environment. In the first three years of planting, watering management should be strengthened. In addition to watering well for the first three times, water 1-2 times each month from April to September depending on temperature and rainfall. July and August are periods of abundant rainfall; if the weather is not particularly dry, water less or not at all. In late November or early December, water thoroughly for freeze protection. In the following year, water well for thawing in early March, control watering during the flowering period, water thoroughly once when new leaves sprout after flowering, and also water 1-2 times from April to September depending on temperature and rainfall. In the third year, management should also follow the watering methods of the first two years. From the fourth year onward, water well for thawing and freeze protection in early March and late November each year. During high-temperature periods in spring and summer, water according to rainfall conditions, and at other times it can rely on natural growth.

Forsythia likes fertilizer. With sufficient fertilizer, the branches and leaves are luxuriant and the flowers are large and brightly colored. When fertilizing forsythia, in addition to applying sufficient base fertilizer at planting, apply dried chicken manure or sesame paste residue once in late autumn of the same year combined with watering for freeze protection. In the second year, apply nitrogen fertilizer once after flowering, apply a phosphorus-potassium compound fertilizer once during the flower bud differentiation period in July and August, and apply dried chicken manure once again in late autumn. After that, management can follow this method every year.

III. Pruning Methods

The common plant shape of forsythia is a clustered round-headed form. After the seedlings are field planted, the selected main branches are heavily shortened to promote branching. During winter pruning, thin and weak branches and root suckers sprouting from the root crown are removed. For weak, thin, curved growth branches, 1/5 of the total length can be cut off, retaining only plump flower buds in the middle of the branch. For upright long flowering branches with relatively vigorous growth and slightly heavier tops, choose 3-4 to leave unpruned, and treat the remaining overly long flowering branches by cutting them back; for water sprouts, heavy shortening can be used to promote more branching and increase flowering branches, or they can be kept as renewal branches for later use.

In addition, forsythia can also be pruned into an umbrella shape. When this plant shape blooms and a breeze blows, it is very graceful and free, and it is often used to decorate rockeries and the like. When planting, choose the most robust branch and shorten it at 40-50 cm from the ground, and remove all other branches. New branches emerge from the top of the retained trunk. Choose 3-4 branches with relatively even distribution and suitable opening angles as main branches, and remove all the rest. Shorten the retained main branches to make them produce more side branches. Because forsythia branches are slender and soft and easily droop, they form an umbrella shape. After the umbrella shape is basically formed, root suckers should be removed frequently, the branches should also be pinched frequently, and overly dense side branches should also be removed to maintain ventilation and light penetration.

IV. Pest and Disease Control

The common disease of forsythia is leaf spot disease, caused by infection by fungi of the class Deuteromycetes. The pathogen first infects the leaf margin, and as the disease develops it gradually spreads toward the middle of the leaf, with a clear distinction between diseased and healthy parts. In the later stage of the disease, the entire leaf withers and dies. This disease begins in mid-to-late May, with July and August as the peak period. High-temperature and high-humidity weather and poor ventilation favor the spread of the disease. To control leaf spot disease, first pay attention to pruning, removing miscellaneous branches and overly dense branches so that the plant maintains ventilation and light penetration; second, strengthen water and fertilizer management, pay attention to nutrient balance, and do not apply too much nitrogen fertilizer. If it occurs, spray 75% chlorothalonil wettable powder 1200 times solution or 50% carbendazim wettable powder 800 times solution for control, once every 10 days. Spraying continuously 3-4 times can effectively control the disease.

Common insect pests of forsythia include: Ricania speculum, Euricania clara, Pseudaulacaspis pentagona, Aspidiotus hederae, round-spotted leaf-rolling weevil, Eudocima sp., pine-oak caterpillar, and white-bearded brown hawk moth.

If they occur, during the period when nymphs gather on branches and cause damage, spray 10% imidacloprid wettable powder 2000 times solution or 25% chlorfenapyr suspension concentrate 1000 times solution to kill Euricania clara and Ricania speculum; during the peak hatching period of nymphs, spray 95% jiemanling emulsifiable concentrate 400 times solution, or 20% sukemie emulsifiable oil 1000 times solution to kill Pseudaulacaspis pentagona; during the adult stage of the round-spotted leaf-rolling weevil, spray 3% high-penetration fenoxycarb emulsifiable oil 3000 times solution for control; during the larval stage of Eudocima sp., spray 20% confidor soluble concentrate 3000 times solution for control; during the young larval stage of the pine-oak caterpillar, spray 3% high-penetration fenoxycarb emulsifiable oil 3000 times solution for control; when white-bearded brown hawk moth damage is severe, spray 1.2% nicotine anabasine 1000 times solution for control.

V. Propagation Methods

The propagation methods of forsythia include: sowing, division, cuttings, and layering.

1. Sowing

After the fruit matures in autumn, collect the fruit and dry it, then beat it to obtain pure seeds. Put the seeds in a clean cloth bag and store them at 5-10°C. In the morning of March of the following year, carry out germination promotion. Soak the seeds in a 1:2000 gibberellin alcohol solution for 4 hours to break dormancy, then mix the seeds thoroughly with wet river sand at a weight ratio of 1:800. Under a temperature condition of 10-20°C, they will germinate in about 30 days. Then sow by the drill method, with a bed width of 150 cm, height of 20 cm, depth of 3 cm, and row spacing of 30 cm, 4 rows per bed. After sowing and covering with soil, press slightly so that the seeds and soil are closely combined, and cover with straw curtains to keep the soil moist. Seedlings emerge in about 20 days. Transplant in the spring of the second year.

2. Cuttings

After the flowering period, select 2-year-old branches from healthy plants free of pests and diseases as cuttings. The cuttings are 12-15 cm long, with a flat upper cut and a horseshoe-shaped lower cut. Each cutting should have no fewer than 3 buds. Before cutting, soak the lower end of the cuttings in ABT rooting agent solution for 30 minutes. The cutting spacing is 10×10 cm, and the depth is 8-10 cm. After cutting, build an arched shed on the cutting bed and provide appropriate shade, keeping it moist. Transplanting can be carried out in the spring of the second year.

3. Layering

In spring, select longer branches, bend them downward and bury them 3-5 cm in the soil. After watering thoroughly, keep the soil moist. They will root in about 2 months. In autumn, cut the front end of the buried part, carry out temporary planting, and field plant in the spring of the second year.

4. Division

After leaf fall in autumn, select robust plants with many suckers, dig them up, split them with a sharp knife, and transplant them with soil.