How to Propagate a Radermachera sinica? A Detailed Guide to Common Propagation Methods

Radermachera sinica can be propagated by sowing, cuttings and layering, and all three methods are suitable for March to April.

The specific propagation methods are as follows:

1. Sowing

From March to April, first soak for 3 to 4 hours, remove and spread out briefly to dry, then mix with sandy soil and scatter on a prepared seedbed, lightly cover with a thin layer of soil, cover with plastic film to retain moisture, and once the seeds sprout remove the film and set up a light shade frame for shading. When 2 to 3 true leaves have grown, transplant with a soil ball at wider spacing, or wait until 4 to 5 large leaves have grown before potting or bag planting, strengthen water and fertilizer management, and they can be sold as commercial seedlings in the same year.

Cuttings

From March to April, when the ambient temperature reaches about 15°C, cut 1- to 2-year-old woody branches, about 15 cm to 20 cm long, remove all leaves, with the lower cut preferably located 0.5 cm below a node, and insert them into a sandy loam seedbed, with the cutting inserted to a depth of about 1/3 to 1/2 of the cutting length. During the period when the lower cut is healing and rooting, spray water to keep the seedbed moist. Only after a well-developed root system has grown should they be transplanted with a soil ball into pots; it is best to plant 2 to 3 together, so they can take shape and be sold early.

Layering

From March to April, on a 2-year-old vigorous branch or stem below a node, carry out ring barking, with the bark removal width generally 2 to 3 times the diameter of the stem being layered. Below the ring-barked wound, tie a piece of 15 cm × 20 cm plastic film. Using clean moist peat soil or sandy loam, press and shape a soil ball 8 cm to 10 cm in diameter at the ring-barked area. Then, wrap the soil ball well with plastic film, leave a water inlet at the upper end, and tie it against a thick main trunk to prevent it from drooping and being broken by wind. By late autumn, after a relatively well-developed root system has grown at the ring-barked wound, cut it away from the mother plant and plant it separately in a pot.

Radermachera sinica has a graceful tree shape and a long flowering period, and is an excellent tree species for garden planting and indoor potting.