Detailed Explanation of Key Techniques for Large-Branch Cutting Propagation of Cherry Blossoms

Cherry blossom propagation previously generally used cherry as rootstock in spring for branch grafting. This method is relatively labor- and material-intensive and is not suitable for the large demand for seedlings in rapidly developing landscaping. In recent years, we have carried out large-branch cutting propagation for seedling cultivation and achieved good results.

1. Selection of cuttings

Select young and robust mother trees, cut annual thick branches from the middle-upper outer part of the canopy, retain the top shoot, cut into 30-40 cm long cuttings, and cut the lower end into a slanted opening. Cuttings cut on the same day must be inserted on the same day to prevent the cuttings from losing water, damaging the cut surface, and tissue necrosis. Be sure to note: thin and weak cuttings will reduce the survival rate, and short cuttings will delay the seedling-growing period.

2. Prepare the cutting bed well

For the cutting bed, choose a site sheltered from the wind, facing the sun, and with good drainage, and make a bed plot 1 m wide and 30 cm high. At the bottom layer of the bed plot, spread 15 cm thick sandy loam soil with a certain fertility, and on the upper layer cover 10 cm of yellow-heart sandy loam soil (prepared with 8 parts yellow-heart loam soil and 2 parts yellow sand), and carry out sterilization treatment.

3. Master the cutting time

Cherry blossoms are deciduous tree species. Annual large-branch cuttings should be carried out before the tree buds sprout. When the soil temperature reaches above 16°C, the cuttings begin to take root.

4. Pay attention to the cutting method

Use a small stick slightly thicker than the cutting to insert vertically into the cutting medium, with a depth of 5-6 cm and a spacing of about 10 cm, then insert the cutting, and press firmly with your hand. After insertion, water thoroughly with a fine-mesh watering can so that the cuttings and soil are closely combined.

5. Manage well after cutting

(1) Maintain moisture and warmth to promote healing and rooting. In early to mid-March, the temperature is generally unstable, rising and falling suddenly. If the temperature drops greatly, emergency measures can be taken by covering with plastic film. If the daily maximum temperature reaches above 15°C, spray once at noon. Later, as the temperature steadily rises, spray 3-4 times a day, preferably so that the surface soil does not turn white. To improve the soil condition and help it form healing tissue as soon as possible, 15-20 days after cutting, apply 2% concentration monopotassium phosphate as a foliar topdressing. After about one month, they will gradually heal and take root.

(2) Build a shade shed. After cutting, set up a frame and prepare for shading. The height of the frame should be slightly higher than a person for easy operation. This is conducive to ventilation and air permeability and creates a microclimate in the cutting bed. When the daily maximum temperature is above 16°C, cover with curtains or use shade netting for shading, with a shading rate of 50-70%, and it is best to cover during the day and uncover at night.

(3) Remove tillers and wipe off buds. The thick cuttings of cherry blossoms are themselves very rich in nutrients, and when sunlight is sufficient and the temperature is too high, the buds and leaves will begin to sprout in large numbers before rooting. At this time, except for retaining the terminal bud, all the rest should be wiped off to avoid excessive consumption of nutrients.

(4) Apply timely topdressing to promote root group growth. To meet the growth requirements of the cuttings, one week after rooting, apply a light fertilizer promptly, and thereafter apply once every 15 days (stop application during severe heat). In this way, after three to four fertilizations, the root groups of the cuttings become well developed and grow vigorously, and they can absorb nutrients from the lower layer in advance. The height in the same year can reach more than 1 m, and in early spring of the next year they can be moved out of the bed for transplanting and cultivated into large seedlings.

(5) Pay attention to disease prevention and pest control. Cherry blossom seedlings are susceptible to damage by diseases and pests, and their leaves are prone to leaf spot disease. Carbendazim at 800 times dilution can be sprayed once every half month. Their terminal buds and tender shoots are prone to shoot borers and aphids. Once newly hatched larvae are found, spray pesticide promptly for control. This is to prevent the seedlings from being damaged.