Detailed Explanation of Forsythia Seedling Cultivation Methods and Key Technical Points
Forsythia is a deciduous shrub that blooms before leafing out, with bright golden-yellow flowers that are lovely and charming. Its capsules are ovoid, and the seeds are winged. It prefers light and tolerates shade, can withstand severe cold down to -50°C, tolerates drought and poor soil but fears waterlogging. The seedling cultivation techniques are described below.
I. Seed Sowing and Seedling Cultivation
1. Seed collection and bud treatment: After harvesting the capsules, spread them out to dry in the sun, remove the wings, and store. The thousand-seed weight is 4.5 grams, the sowing rate is 100 grams per 10 sq m, and the seedling yield is 3000 plants per 10 sq m. In early April, carry out seed treatment: disinfect with 0.5% potassium permanganate solution for 3 hours, soak in 30°C warm water for 48 hours, then remove and mix with 3 times the volume of river sand, and place indoors at 10°C to 20°C. Turn frequently to maintain the seed-sand moisture at 60%. After 40 days, when one-third of the seeds have split open, sow.
2. Bed preparation and sowing: Choose a dry, well-drained plot and make beds 10 m long, 15 cm high, and 1 m wide. For every 30 jin of bed soil, mix in 5 grams of quintozene and 5 grams of zineb to make medicated soil. Before sowing, spread a layer of medicated soil; after drilling or broadcasting, cover with soil to a thickness 3 times the seed diameter. Press firm and water thoroughly, then apply a solution of oxadiazon to kill weed sprouts, and do not water for 10 hours.
3. Seedling stage management and overwintering: After sowing, keep the bed surface moist, loosen the soil and apply fertilizer at appropriate times. The current-year seedlings can reach 60 to 90 cm in height. After leaf fall and before the ground freezes, dig up the seedlings, grade them, and heel them in. The following spring, when planting during the early thaw, transplant them into ridges to grow larger seedlings.
II. Cutting Propagation
1. Shoot collection and cutting preparation: Select healthy 1- to 2-year-old branches free of pests and diseases. Cuttings should be 10 to 15 cm long and 0.3 to 1.5 cm in diameter, with 1 to 2 strong buds at the top. The cut should be smooth, with the lower end cut into a 45-degree slant. In late autumn to early winter or before sap flow in early spring, collect and cut at the same time, then bury in sand. Carry out cuttings in July.
2. Bed preparation and cutting: Prepare the bed the same as for seed sowing. Fill the bottom of the bed with 20 cm of fermenting material, then add 20 cm of bed soil and substrate, rake level, press firm, and water thoroughly. Before inserting, soak the cuttings in clean water for two days, then soak the bases in 50 ppm ABT rooting powder for 2 to 4 hours. Set cuttings at a spacing of 10 to 15 cm and a depth of 6 to 10 cm, then water thoroughly.
3. Building the frame and management: After inserting, build a small arched frame 60 cm high and cover with plastic film. Water once every 1 to 2 days, keeping the bed surface moist without standing water, at 70% to 90% humidity, with a soil temperature of 23°C to 24°C and an air temperature of 25°C to 28°C. After about 20 days, leaves emerge and roots form. During this period, weed, loosen the soil, and apply fertilizer.
III. Layering Propagation
In early spring, select vigorous branches, dig a pit 20 cm deep, scrape the bark of the branch, press it into the pit, cover with soil, firm it, and water. After the branch roots and sends out new shoots, cut it off to form a new plant.
IV. Root Division Propagation
In early spring, loosen the soil, apply fertilizer, and water in a ring 70 cm from the mother plant beneath the crown, so that the surface roots sprout and produce new plants. Through artificial tending, seedlings meeting landscaping standards are produced. Layering and root division propagation methods are generally used less often.