How to Grow Forsythia: Latest Planting Techniques and Methods Tutorial

Forsythia, also known as Huangshoudan, Huanghuagan, Huangshoudai and Shoudaidan, belongs to the genus Forsythia in the family Oleaceae. It is produced in the northern, central and northeastern provinces of China, and is now widely 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. Below, the editor will introduce the cultivation techniques of forsythia for reference.

Growth habits of forsythia

Forsythia likes light and has a certain degree of shade tolerance; it likes warm, humid climates and is also very cold-resistant; it is tolerant of drought and barren conditions, but fears waterlogging; it is not choosy about soil and can grow normally in neutral, slightly acidic or alkaline soils.

It can grow on dry sunny slopes or in soil-filled rock crevices, and even on weathered parent material of bedrock or purple sandstone and shale. Forsythia has a well-developed root system. Although the main root is not very prominent, its lateral roots are relatively thick and long, and its fibrous roots are numerous, extending 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 low temperatures of -50°C. Its amazing cold resistance makes it an outstanding choice for garden greening in the north; forsythia has strong sprouting ability and quickly forms clumps, allowing it to rapidly expand its distribution range. Therefore, forsythia has very strong vitality and adaptability.

Experiments show that forsythia can grow normally in areas with an altitude of 250 m-2200 m, an average temperature of 12.1°C-17.3°C, an absolute maximum temperature of 36°C-39.4°C, and an absolute minimum temperature of -4.8°C-14.5°C, but it grows better under site conditions with sufficient sunlight and deep, fertile and moist soil.

Propagation techniques of forsythia

Forsythia can be propagated by seeds, cuttings, layering, division and other methods. In production, seed propagation and cutting propagation are the main methods.

1. Seed propagation

① Seed collection: Select superior mother plants. Choose superior individual plants that grow robustly, have short and thick internodes, dense and plump flowers and fruits, no pests or diseases, and pure variety as mother trees. Pay attention to observing the flowering and fruiting periods and grasp the appropriate seed collection time. Collection should be timely to avoid the seeds falling off by themselves after maturity. Generally, mature fruits are collected from mid-to-late September to early October. Collect fully developed forsythia fruits with plump seeds that are large and heavy, then spread them thinly in a ventilated and shady place, and thresh them after drying in the shade. After careful selection and removal of impurities, choose neat, plump seeds free of pests and diseases and store them for seed.

② Seed storage: Storing forsythia seeds under different conditions has a great impact on their germination rate. A Beijing research institute collected forsythia seeds in 1977 and stored them in a chicken-heart bottle at room temperature. By February 26, 1979, the measured germination rate was 43.7%. According to experiments by the Hainan Drug Station: forsythia seeds are better stored in a desiccator. After 11 months of storage, the emergence rate could still reach 85.3%; when stored in sand for 7 months, the emergence rate dropped to 31.3%; after more than 8 months of storage, germination ability was completely lost. With wet sand storage, the seeds germinated one after another during storage, so the emergence rate after sowing was not as high as with desiccator storage.

③ Seed germination: Forsythia seeds germinate easily. It should be said that the seeds are suitable for germination at relatively high temperatures. Based on seed storage and germination conditions, combined with practical experience, cultivation time can be arranged in spring or winter. Spring sowing is in mid-to-late April, and winter sowing is carried out before the soil freezes.

④ Seed seedling raising: The seed coat of forsythia seeds is relatively hard. If sown directly in the nursery without pretreatment, it takes more than 1 month for them to germinate and emerge. Therefore, germination acceleration treatment can be carried out before sowing. This method can be used in newly introduced planting areas. The specific method is: choose mature and plump seeds, soak them in warm water at about 30°C for about 4 hours, remove them, mix them with 3 times their volume of wet sand, place them in a wooden box or small vat, cover the top with plastic film, and place them in a windproof and sunny place. Turn them twice a day and keep them moist regularly. After more than 10 days, the seeds sprout and can be sown. After sowing, seedlings can emerge in 8-9 days, about 20 days earlier than seeds without pretreatment. If the land is dry, first water the seedbed, and sow when the water has seeped down and the surface soil is slightly loose. Spring sowing is around “Qingming”, and winter sowing is before the soil freezes (the seeds do not need treatment and can emerge the next year).

⑤ Seed sowing: When sowing seeds, on the prepared seedbed surface, open furrows 1 cm deep at a row spacing of 20—25 cm, mix the seeds with fine sand, evenly sprinkle them into the furrows, cover with soil and rake level, and press lightly. Seedlings can emerge in 10-15 days. The seeding rate per mu is about 2-3 kg. The soil covering must not be too thick, generally about 1 cm, and then cover with grass to maintain moisture. After the seeds emerge, remove the grass promptly. When the seedlings are 10 cm high, thin them to a plant spacing of 10 cm. In early April of the second year, when the seedlings are about 30 cm high, they can be transplanted to the field.

⑥ Direct sowing in the field: Open holes at a row spacing of 2 m and a plant spacing of 1.5 m, apply compost and plant ash, and mix with soil. Start sowing from late March to early April, or sow before the soil freezes in late autumn. Sow more than 10 seeds per hole, cover with soil after sowing, and press lightly. Note that sowing should be done when soil moisture is good.

2. Layering propagation

Layering propagation is to bury the drooping branches of the plant into the soil in spring and cut them from the mother plant for planting in the following spring. Generally, cutting propagation is the main method. Seedlings should be planted in fertile soil that is sunny and well-drained. If the site is improperly chosen and the soil is barren, growth will be slow and yield low. After flowering each year, dead branches, weak branches and overly dense or old branches should be pruned, and attention should also be paid to fertilizing around the roots.

3. Cutting propagation

Cuttings can be taken after leaf fall in autumn or before germination in spring, but spring is better. Select robust young branches 1-2 years old, cut them into cuttings 20—30 cm long. The cut at the upper end should be 0.8 cm from the first node, and each cutting must have 2-3 nodes. Then cut the lower end near the node into a flat surface. To improve the survival rate of cuttings, tie the cuttings into bundles of 30—50, soak the base of the cuttings (at 1-2 cm) for 10 seconds in 500 ppm ABT rooting powder or 500—1000 ppm indolebutyric acid solution, take them out and dry them before inserting.

In the south, cuttings are mostly taken in open ground in early spring, while in the north they are mostly taken in summer. Before cutting, rake the seedbed fine and level it, make a high bed 1.5 m wide, and insert the cuttings obliquely into the bed at a row and plant spacing of 20×10 cm, inserting them 18-20 cm deep into the soil, leaving the topmost node of the branch exposed above the ground, then cover with soil and compact it. In dry weather, water frequently to keep the soil moist, but not too wet, otherwise the part of the cutting in the soil will turn black and rot. With normal management, the cutting seedling rate can reach as high as 90%. With strengthened field management, the seedlings can reach more than 50 cm in height after autumn and can be planted in holes in the following spring.

4. Division propagation

After “Shuangjiang” or before germination in spring, dig out the young shoots growing beside trees more than 3 years old with soil and transplant them, or dig out the entire tree and divide it for transplanting. Generally, one plant can be divided into 3-5 plants. The key to this method is to ensure that each divided small plant has some fibrous roots, so that the survival rate is high and results are quick.