Detailed Explanation of Key Techniques for Autumn Rose Cuttings
Roses can be propagated from cuttings in all four seasons, but the autumn cutting method is simple, easy to manage after winter sets in, and after being divided and potted the following year, they can bloom that same year. September to October, with temperatures of 20°C to 25°C, is the best time for rose cuttings, with a survival rate as high as over 95%.
Seedbed preparation
For cutting propagation, it is advisable to choose neutral sandy loam soil with good water and fertilizer conditions (pH 6.5 to 7). If the soil is heavy and clayey, an appropriate amount of fine sand can be mixed in during soil preparation. If the soil has a high sand content and low fertility, an appropriate amount of organic fertilizer can be applied during soil preparation. Combined with soil preparation, apply 0.5 kg of isofenphos-methyl per mu to prevent underground pests from damaging the seedlings. For home propagation, shallow clay pots or shallow wooden boxes can be used, with a soil mix that is loose, well-draining, well-aerated, and free of root-nodule bacteria, such as 7 parts loose garden soil plus 3 parts rice husk ash or perlite. Before use, it is best to spread the above substrate on a concrete surface and expose it to sunlight, or disinfect it with a chemical solution to kill soil-borne pathogens, then fill it into pots or boxes for cuttings.
Selection and pruning of cuttings
In the cutting orchard, select healthy, pest-free, high-quality plants as mother plants. From the mother plants, choose branches that are thick and strong, have short internodes, good lignification, and fully developed leaves, either after flowering or before flowering, as cuttings. The cutting should retain 4 nodes (i.e., 3 compound leaves), with a stem length of about 10 cm being appropriate. The top leaf should be 1 cm from the upper cut, and the upper cut should be made flat. The lower end is cut off below the third compound leaf, and a horse-ear shape is cut on the lower part opposite the compound leaf. The first and second compound leaves must be robust and complete, with each compound leaf retaining 2 small leaflets, and the rest cut off together with the petiole. The lower cut of the cutting should be made into a horse-ear shape at the base of the stem behind the bud eye of the third compound leaf, to make full use of the favorable factor of abundant nutrient storage in the internodes, so that the cutting heals and roots easily and survives.
Pre-cutting rooting treatment
Soaking method: Use No. 2 ABT rooting powder at 30 ppm to 50 ppm solution. Tie 50 to 100 cuttings into 1 bundle, soak the lower 2 cm in the solution for 2 to 4 hours, then remove and insert into the seedbed at a depth of 3 cm to 5 cm.
Quick-dip method: Prepare a 500 ppm solution using 50% alcohol and naphthaleneacetic acid or indolebutyric acid. Dip the lower 2 cm of the cuttings into the solution for 2 to 5 seconds, and once the solution is slightly dry, immediately insert them into the seedbed. To prevent the cuttings from rotting due to pathogen invasion during rooting, 2.5% Kejunkang can also be added when preparing the rooting agent.
Cutting method
Rose cuttings mostly use the straight insertion method. The insertion depth is 1/3 to 1/2 of the cutting length, generally deep enough to reach the second bud eye. When inserting, first make a hole with a bamboo stick of the same thickness as the cutting, then insert the rose cutting and press firm. The planting density should be such that the leaves do not touch each other. When inserting, long cuttings and short cuttings should be inserted separately to prevent uneven lengths and irregularity, which would affect light and growth. At the same time, varieties should not be mixed; insert in sections by variety, arranged neatly and orderly for easy management. After insertion, immediately water with a fine-rose watering can; do not spray too forcefully, so as to avoid mud contaminating the cutting leaves or washing out the cuttings. Cover with plastic film to maintain temperature and humidity in the bed.
Post-cutting management
After cutting, water thoroughly, then use a small plastic-film tunnel to shade and retain moisture. For the first 10 days, spray water frequently to maintain a relatively moist environment; after 10 days, control spraying, spraying only when dry, and keep it in a drying state. In an environment of 20°C to 25°C, the cuttings can root in 20 to 35 days, with a rooting rate of 95%. After new roots form, water and fertilize in a timely manner to promote balanced growth of the seedling above and below ground. Management is divided into three stages, each lasting 7 to 10 days. The first stage is the shade and moisture stage; at this time, avoid direct sunlight, cover with a curtain promptly on sunny days, and when the leaves are dry, use a small sprayer to mist the leaf surface to prevent the leaves from withering and falling off. The second stage is the healing stage. At this time, the wound begins to heal; prevent excessive moisture, otherwise the wound tissue will rot and become moldy, and gradually let the potting soil dry out. In the morning and evening, increase the time of weak sunlight exposure to promote photosynthesis. The third stage is the rooting stage; sunlight exposure time can be gradually increased, and when the potting soil is dry, water appropriately. If the old leaves do not fall off and new buds have grown, it indicates that roots have developed and the cutting has survived.