When is the Best Time to Propagate Osmanthus Trees in the North
As a plant that offers both economic and ornamental value to northern courtyards, the survival rate of osmanthus tree cuttings directly affects planting profits. Mastering the scientific timing and techniques of propagation can increase the rooting rate of branches to over 90%. This article systematically analyzes the propagation techniques of osmanthus trees in the north, starting from phenological characteristics and regional climates.
Ⅰ. Choosing the Golden Period for Propagating Osmanthus in the North
1.1 The Best Spring Propagation Period
In the North China region, operations should be performed from early May to mid-June, when the average daily temperature stabilizes between 18-25°C. Early propagation may encounter late spring frosts, while late propagation may lead to霉变 of cuttings during the plum rain season. It is recommended to combine phenological observations and collect branches when the mother plant's new shoots are half lignified.
1.2 The Autumn Propagation Window
From late September to mid-October is the second suitable period, ensuring that the roots have a 30-day growth period after propagation. Special attention should be paid to avoiding early frosts; when night temperatures consistently drop below 10°C, a small arch greenhouse should be set up for insulation.
Ⅱ. Detailed Explanation of the Full Propagation Process
2.1 Scientific Cutting Treatment
Select one-year-old half-lignified branches, retaining three bud nodes (about 15cm). Use a 45° oblique cut to increase the water absorption area, with the upper cut flat and 0.5cm away from the top bud. Soak in ABT1 rooting powder at 1000ppm for 10 minutes to activate callus formation.
2.2 Optimization of Substrate Formula
It is recommended to use a mixed substrate of perlite: vermiculite: humus soil in a ratio of 4:3:3, adjusting the pH to 5.5-6.5. Adding 50g of sulfur powder per cubic meter can maintain an acidic environment for an extended period, with a substrate thickness of over 25cm to ensure root development space.
2.3 Precise Propagation Operation
Use the direct insertion method, with the depth of insertion being 1/3-1/2 the length of the cutting (about 5-8cm). Maintain a spacing of 8×10cm, and gently press the substrate after insertion to ensure close contact. Immediately water thoroughly to stabilize the roots and cover with 70% shade net to avoid direct sunlight.
Ⅲ. Key Points for Post-Propagation Maintenance
Maintain air humidity at 80%-90% and substrate moisture content at around 60%. Spray 0.1% potassium dihydrogen phosphate foliar fertilizer every 7 days, and gradually increase light exposure after 20 days. When new shoots are over 5cm long, it indicates that the roots have matured and can be transplanted.
By accurately grasping the phenological period, scientifically preparing the substrate, and following standardized operation procedures, it is possible to achieve a survival rate of over 95% for osmanthus propagation in the north. It is recommended to establish a propagation log to record temperature and humidity changes and rooting conditions, accumulating data support for large-scale breeding.