A Detailed Explanation of Forsythia Propagation Methods and Cultivation Management Techniques

Forsythia is an excellent ornamental flowering shrub for early spring in cities. Its optimum growth temperature is around 20°C to 25°C, and it can withstand low temperatures of -10°C in winter. Forsythia grows mainly in fertile, loose neutral, slightly acidic or slightly alkaline soil. Below, let us learn together about forsythia propagation methods and seedling-stage management.

1 Propagation

1.1 Seed propagation

Forsythia seed propagation is mostly carried out in early spring.

① Seed collection. Select healthy, pest- and disease-free forsythia mother plants as mother trees. In September to October, collect fully mature forsythia fruit and spread it on the ground in a sheltered, shady place. After thorough air-drying in the shade, thresh it, remove impurities and damaged seeds, select good seeds, and put them in cloth bags or gunny bags placed in a ventilated spot.

② Nursery site preparation. Choose fertile, loose neutral soil with convenient water sources and transportation as the nursery site. Before cultivation, clear the tree roots, weeds, and stones from the nursery site. In late autumn and early winter, deep-plow the nursery site once to a depth of 35 cm. Do not harrow; let it go through one winter of freezing to facilitate soil weathering and improve the soil's physical and chemical properties. By mid-to-late February of the following year, broadcast 80 kg of compound fertilizer per mu, or 200 kg of fully decomposed cake fertilizer per mu, and harrow the field 2 to 3 times continuously with machinery so that the nursery site is fully leveled, the soil clods are broken up, and the fertilizer is evenly mixed into the soil particles.

③ Digging trenches and making beds. Manually mark lines at a width of 1.5 m, dig trenches, and make seedling beds, in which the bed width is 1.2 m, the trench width is 0.3 m, and the trench depth is 0.25 m. At the same time, dig the drainage ditches around the nursery site (commonly called perimeter ditches) and dig the middle ditches of the seedling field, 0.4 m wide and 0.35 m deep. Evenly spread the fertile soil from the ditches onto the seedling beds to increase the fertile soil layer. For nursery sites where pests and diseases occur, it is best to carry out one disinfection, sterilization, and insect-killing operation before sowing. You can use drugs such as "Bingchong Yisaoguang" mixed with fine soil and broadcast it in advance, or use dexon (1 to 1.5 kg/mu) or ferrous sulfate (15 to 20 kg/mu) mixed with fine soil and broadcast it.

④ Sowing. In mid-March, take out the dry-stored forsythia seeds, remove moldy and non-germinating seeds, and further carefully select them. Soak the seeds in cold water for 6 to 8 hours so that the seeds fully absorb water and become saturated, then scoop them out, drain them, and sow. Open drill sowing trenches 1.5 cm deep with a row spacing of 25 cm. Evenly sow the forsythia seeds in the trenches, cover with 1 cm of fine soil after sowing, and then cover with pine needles, rice straw, sawdust, etc., to preserve moisture and allow air circulation, and often maintain suitable humidity. Seedlings emerge around late April. After emergence, remove the pine needles and rice straw, and spray with a diluted 1000-fold carbendazim solution about every 10 days for sterilization. If there are insect pests, spray with a diluted 2500-fold deltamethrin solution 1 to 2 times, which can achieve a good effect. With proper management, the seedlings can reach 40 to 60 cm in height in the same year.

⑤ Seedling transplanting. To make forsythia planting neat, the method of seedling transplanting can be used. In late March, choose a sheltered, sunny place to make a sand bed. The sand bed is 1 m wide and no more than 12 m long. Use a wooden board to flatten the sand bed, with the four edges of the sand bed 1 cm higher than the bed. First spray thoroughly with a diluted 1000-fold potassium permanganate solution for sterilization. Evenly broadcast the soaked forsythia seeds (with embryo buds not yet breaking through the seed coat) on the sand bed, first cover with 1 cm of fine sand, then gently flatten with a small wooden board (already disinfected) so that the seeds and river sand are fully in contact. Water thoroughly with a watering can, set up a small arched shed, cover with 2 m wide medium film, and press the edges of the film firmly with bricks or clods of soil. After sowing, observe the sand bed frequently. The seeds germinate and emerge in about 15 to 20 days. Pay attention to the temperature and humidity of the small arched shed. When it exceeds 30°C, shade it or open both ends for ventilation. Once the sand turns white, water appropriately to prevent seedling scorching. After hardening the seedlings for a period, seedling transplanting can be carried out, about 10,000 to 15,000 plants per mu. Water while planting to increase the survival rate.

1.2 Cutting propagation

Cutting propagation can be divided into hardwood cuttings and softwood cuttings. Hardwood cuttings are carried out in early spring from February to March, and softwood cuttings are carried out from May to July.

① Hardwood cuttings. In early spring from February to March, use fully lignified branches of forsythia from the previous 1 to 2 years. Nursery site preparation is the same as for sowing, and no fertilizer at all is applied to the cutting nursery site. Level the soil on the seedling bed finely and break up clods, with the middle slightly higher to form a turtle-back structure, to facilitate cutting operations and drainage. Set up a shade shed and put on 50% shade netting. Twenty-four hours before cutting, water thoroughly with a diluted 1000-fold potassium permanganate solution for sterilization.

In spring from February to March, collect 1- to 2-year-old forsythia branches and pile them indoors. Shorten the branches into 15 cm cuttings, cut from the nodes, with 2 to 3 buds on the upper part. Make bundles of 30 to 50 cuttings, align the top and bottom, quickly dip the lower ends in 0.1% IBA (indolebutyric acid) solution for 5 to 10 seconds, drain slightly, and then insert into the soil to a depth of 10 cm. After finishing one bed, water thoroughly, set up a small arched shed, cover fully with 2 m wide film, and press the edges of the film firmly with stones or clods of soil. After the entire cutting base is finished, hang a thermometer and hygrometer in one of the small arched sheds.

Within 20 days after forsythia cutting, keep the air humidity inside the small arched shed above 90% and the temperature below 38°C. Callus formation and rooting begin at about 20 days, rooting can occur at 30 days, and some cuttings begin to unfold leaves. At this time, ventilation and seedling hardening can be carried out gradually. Open the film at one end of the small arched shed, then after 2 to 3 days open the film at the other end, and after 2 to 3 days the small arched shed can be completely removed, but suitable humidity in the seedling bed still needs to be maintained. After sufficient hardening, the shade netting can be removed for full-light hardening. Transplant the seedlings to the field in autumn.

② Softwood cuttings. Use current-year semi-lignified branches.

The time for forsythia softwood cuttings is summer from May to July. At this time, the temperature is high, sunlight is strong, and transpiration is fast, so cuttings are prone to dehydration and death. Therefore, about 90% shade netting needs to be set up, with the nets connected in the middle by sturdy rope. The surroundings of the netting are fixed to wooden stakes with wire and rope to ensure that direct sunlight cannot reach the seedling bed.

Ten days before forsythia cutting, spray the forsythia mother plants' leaves with monopotassium phosphate plus DuPont Yibao to supplement nutrients and sterilize, and spray once more after 5 days. If there is dry weather, irrigate heavily once 1 to 2 days before cutting.

For softwood cuttings, collect cuttings as much as possible before sunrise or on rainy days. Pile the collected branches indoors and spray water frequently to preserve moisture, to prevent the branches from dehydrating and losing vitality. Indoors, cut the branches into 8 to 15 cm lengths, make bundles of 30 to 50, and cut the cuttings from the nodes. Quickly dip the lower ends in 0.1% IBA (indolebutyric acid) for 5 to 10 seconds. Use a small wooden stick of the same thickness as the cuttings to make holes in the cutting bed, then place the treated cuttings into the holes and press firmly with your hand. After inserting, water thoroughly so that the substrate and cuttings are tightly combined, spray the leaves with a 1000-fold carbendazim solution, immediately set up a small arched shed, seal it all around, and cover with 50% shade netting close to the film.

Post-cutting management is the same as for hardwood cuttings. When forsythia has fully rooted and more than 50% have sprouted, gradually remove the small arched shed and shade netting after hardening the seedlings.

2 Seedling-stage management

2.1 Thinning and filling in seedlings

When forsythia seedlings grown from seed reach 5 to 10 cm, reasonable thinning should be carried out, and filling in of gaps should be done together with thinning. Use a small pointed trowel to dig up dense seedlings together with soil, then immediately replant them in sparse areas and water and firm the soil. Afterward, water according to drought conditions to ensure survival. When seedling growth is basically stable, final thinning can be done, maintaining about 10,000 to 15,000 plants per mu.

2.2 Weeding

For weeds in the sown seedling beds, perimeter ditches, middle ditches, and bed ditches, they can be directly removed with hoes and shovels. For cutting beds, only a small shovel can be used to remove weeds little by little, followed by watering and firming the soil. Generally, weeding is needed twice from May to July, and once a month from August to October.

2.3 Water and fertilizer management

Spring irrigation should follow the principle of small amounts and frequent applications, alternating dry and wet. During the plum rain season, pay attention to clearing ditches and draining silt. In summer drought, water thoroughly with a large amount. In autumn and winter, water less or not at all. In summer, topdressing can be combined with watering. From June to August, apply 5 kg of urea per mu each time to sown seedlings, once every 15 days. For cutting seedlings, use foliar topdressing with a 0.2% to 0.3% monopotassium phosphate aqueous solution. Stop topdressing after August 15 to allow forsythia seedlings' shoot tips to lignify, which is beneficial for overwintering.

3 Pest and disease control

Common diseases include crown gall, leaf spot, and shoot blight, which can be controlled by spraying Bordeaux mixture or 65% zineb wettable powder 800-fold solution. Pests include aphids, nettle grubs, plant bugs, and weevils, which can be killed by spraying 40% omethoate emulsifiable concentrate 1000-fold solution.

4 Cultivation management

Forsythia seedlings are transplanted during the deciduous period. Flowers are mostly borne on one-year-old branches. After flowering each year, severely prune aging branches and one-year-old branches to promote the sprouting of new branches. For vigorously growing new shoots, also shorten them in summer. Before planting in winter, apply sufficient base fertilizer. During the growing season, compound fertilizer can be applied in holes, using rainwater to infiltrate and achieve topdressing. Maintain sufficient sunlight and moderately moist soil, and spring flowering will be even more abundant.

The above is all the content on forsythia propagation methods and seedling-stage management. Grower friends are welcome to refer to and learn from it on Huinong.com!

Key Points for the Cultivation and Management of Flowering Almond

Flowering almond (Prunus triloba) is named for its leaves, which are very similar to those of the elm. In Northeast China, because its flowers are very similar to peach blossoms, it is also called "little peach red." Flowering almond has dense flowers, so its ornamental value is relatively high, and it is also a major spring flowering plant in Beijing.

Flowering almond

It is native to the semi-arid mountainous areas of North China and southern Northeast China, mostly distributed on sunny slopes and semi-sunny slopes at an altitude of 500-1200 m. It is a sun-loving tree that prefers well-drained dry gravelly soil. Moist and fertile soil is most suitable for cultivation. It is cold-resistant and dislikes waterlogging. It is cultivated in all areas north of the Yellow River basin. Seed propagation mostly does not easily maintain the traits of the original mother plant, so selection is necessary. Therefore, cultivation generally uses single-petaled seedlings or mountain peach as rootstock for grafting. Grafting by branch can flower the second year; after budding, one year of growth can also form flower buds.

The cultivation and management of flowering almond can be very extensive, but attention should be paid to pruning and removing rootstock suckers. Its flowers all form on the current year's branches, so after flowering the old branches should be renewed and weak branches removed. After the onset of the dog days, another round of pruning and pinching back should be carried out so that nutrients are concentrated for flower bud differentiation, resulting in more and larger flowers the next year. After re-pruning, fertilizer and water should also be applied in time to ensure the plants are robust.

During the spring flowering period, flowering almond is prone to tent caterpillars. If web-like substances are seen on the branches, that is the beginning of their damage. They should be removed immediately, and then spray 1500-fold dimethoate or 1000-fold trichlorfon. There may sometimes be a second outbreak at the end of summer, and the same treatment should be used. In summer there are also leaf-eating pests such as nettle grubs, boat-shaped caterpillars, and bagworms (dumpling worms), as well as aphids and red spiders, which can be killed by spraying 1500-fold dimethoate, 1000-fold trichlorfon, or 1% tobacco leaf water. Flowering almond is best planted in combination with redbud, forsythia, and lilac; the flowers can be used as cut flowers for vases.

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 our country, and is now cultivated in many places. In spring, forsythia blooms all over the tree, and its golden branches sway in the spring breeze in a very natural and elegant way. It is an important early-spring flowering shrub. Its key planting points are introduced below for reference only.

I. Morphological characteristics and biological characteristics

Forsythia is a deciduous shrub that can reach 3 m in height. Its trunks are clustered, upright, with spreading branches that arch and droop; branchlets are yellowish brown, slightly four-angled, with obvious white lenticels, and hollow pith. Leaves are simple or 3-foliolate, opposite, ovate to elliptic-ovate, 4-9 cm long, hairless, with acute tips, rounded to broadly cuneate bases, and coarsely serrate margins. It flowers before leafing out. Flowers are often solitary, rarely 3 in axillary clusters; calyx lobes 4, oblong; corolla golden yellow, lobes 4, obovate-elliptic; stamens 2; there are two flower forms, one with stamens longer than pistils, and one with pistils longer than stamens, and the two flower forms do not grow on the same plant. Flowering period is April to May. Capsules are ovate, 2-locular, seeds winged, fruiting period June to September.

Forsythia likes light but has some shade tolerance. It can grow normally in sparse forests, but the amount of flowers is not as abundant 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; water accumulation easily causes root rot and plant death. It has low requirements for soil and can grow normally in loam, plain sandy soil, and light clay, but grows best in sandy loam and plain sandy soil. It has a certain tolerance to salinity and alkalinity and grows well in saline-alkaline soil with pH 08.8 and a salt content of 0.2%.

II. Water and fertilizer management

Forsythia is drought-tolerant but prefers a moist environment. In the first three years of planting, watering management should be strengthened. In addition to watering well for the first three waterings, water 1 to 2 times per month from April to September depending on temperature and rainfall. July and August are the abundant rainfall periods; 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. During the flowering period, watering should be controlled. After flowering, when new leaves sprout, water thoroughly once. From April to September, also water 1 to 2 times 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, each year water well for thawing and freeze protection in early March and late November, water according to rainfall during high-temperature periods in spring and summer, and rely on natural growth at other times.

Forsythia likes fertilizer. With sufficient fertilizer, branches and leaves are luxuriant and 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 together with freeze-protection watering, apply a nitrogen fertilizer once after flowering the next year, 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. Thereafter, management can follow this method each year.

III. Pruning methods

The common plant form of forsythia is a clustered round-headed shape. After the seedlings are planted, heavily shorten the selected main branches to promote branching. During winter pruning, remove thin and weak branches and root suckers sprouting from the root crown. For thin, curved branches with weaker growth, cut off 1/5 of the total length, retaining only plump flower buds in the middle of the branch. For upright long flowering branches that grow vigorously with slightly heavier tips, choose 3 to 4 and leave them unpruned, and treat the remaining overly long flowering branches by retrenchment. For water sprouts, heavily shorten them to promote more branching and increase flowering branches, or keep them as renewal branches for reserve.

In addition, forsythia can also be pruned into an umbrella shape. With this plant form, when the flowers bloom and a breeze blows, it is very elegant and free-spirited, 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 above the ground, and remove all other branches. New branches sprout from the top of the retained trunk. Choose 3 to 4 branches with relatively even distribution and suitable opening angles as main branches, remove all the rest, and shorten the retained main branches to make them produce more lateral branches. Because forsythia branches are slender and soft and tend to droop, it can be shaped into an umbrella form. After the umbrella shape is basically formed, root suckers should be removed frequently, the branches should also be pinched back frequently, and overly dense lateral branches should also be removed to maintain ventilation and light penetration.

IV. Pest and disease control

The common disease of forsythia is leaf spot, caused by infection by imperfect fungi. The pathogen first infects the leaf margins, 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 late stage of the disease, the entire leaf withers and dies. This disease begins in mid-to-late May, with peak incidence in July and August. High-temperature, high-humidity weather and poor ventilation favor the spread of the disease. To control leaf spot, first pay attention to pruning, removing redundant and overly dense branches so that the plants maintain ventilation and light penetration. Second, strengthen water and fertilizer management, pay attention to nutrient balance, and do not apply excessive nitrogen fertilizer. If it occurs, spray 75% chlorothalonil wettable granules 1200-fold solution or 50% carbendazim wettable granules 800-fold solution for control, once every 10 days, and 3 to 4 consecutive sprays can effectively control the disease.

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

If they occur, during the period when nymphs gather on branches to cause damage, spray 10% imidacloprid wettable granules 2000-fold solution or 25% chujin suspending agent 1000-fold solution to kill Euricania clara and Ricania speculum; during the peak hatching period of nymphs, spray 95% jiemanling emulsifiable concentrate 400-fold solution, or 20% sukemi emulsifiable concentrate 1000-fold solution to kill Pseudaulacaspis pentagona; during the adult stage of the round-spotted leaf-rolling weevil, spray 3% high-penetration fenoxycarb emulsifiable concentrate 3000-fold solution for killing; during the larval stage of the dazzling noctuid, spray 20% kangfuduo concentrated soluble agent 3000-fold solution for killing; during the young larval stage of the pine-oak caterpillar, spray 3% high-penetration fenoxycarb emulsifiable concentrate 3000-fold solution for killing; when white-bearded brown hawk moth damage is severe, spray 1.2% nicotine-matrine 1000-fold solution for killing.

V. Propagation methods

Forsythia propagation methods include: sowing, division, cutting, and layering.

1. Sowing

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

2. Cutting

After the flowering period, select two-year-old branches from robust 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, and each cutting has no fewer than 3 buds. Before cutting, soak the lower ends of the cuttings in an ABT rooting agent solution for 30 minutes. The planting spacing for cuttings is 10 x 10 cm, and the depth is 8-10 cm. After cutting, set up an arched shed on the cutting bed, provide appropriate shading, and keep it moist. Transplanting can be carried out in spring of the second year.

3. Layering

In spring, choose longer branches, bend them downward and bury them in the soil 3-5 cm. After watering sufficiently, keep the soil moist. They can root in about 2 months. In autumn, cut off the front end of the buried part, heel them in, and plant them in the field in spring of the second year.

4. Division

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