Key Points for Winter Production Techniques of Cut Rose in Northern China

The off-season production of roses requires the flowering period to be from September to April of the following year. Therefore, management must include both summer control of top growth and promotion of root development, as well as winter greenhouse management. Varieties with strong adaptability can be selected, such as Xianyi Shangjiao, Sabensha, etc.

1. Fertilization and density requirements: Before planting roses, sufficient base fertilizer should be applied. Generally, 5 cubic meters of farmyard manure and 2 cubic meters of chicken manure per greenhouse, mix well and plow into the ground, then rake level. Make beds in a north-south direction, bed width 1 m, length limited by the greenhouse width. Each bed can plant two rows, row spacing 0.4 m, plant spacing 0.3 m, generally 7-8 plants per sq m is suitable.

2. Planting time: Planting can be done in three seasons throughout the year: first, in April before branches sprout; second, from mid-July to mid-August; third, after Frost's Descent and leaf fall. Depending on conditions, generally spring planting with summer control of top growth and promotion of root development management produces high flower yields in winter of the same year; planting from mid-July to early August can also produce flowers normally in winter; planting after Frost's Descent results in low flower yields in the same year.

3. Post-planting management: (1) Water immediately after planting, water once every 3-4 days, for 3 consecutive times; no fertilization during the seedling recovery period. (2) Pruning is an important management measure for off-season rose production. From late May to September, force them into dormancy, meaning only keep branches and leaves for photosynthesis to accumulate nutrients; remove upper tender buds at any time, but keep basal shoots at the base, allowing them to grow but not bloom, and remove upper buds as soon as they sprout. Starting from September, keep only 1 weaker-growing branch on the whole plant as a supplying branch, and cut back all other branches to 3 buds, cultivate the new shoots into flowering branches, keep the basal shoots on these branches, remove upper buds, and cut flowers when buds appear on the branches. When cutting flowers, still cut back to 3 buds at the base, repeating this process. In this way, fresh flowers can be produced for 5-6 years, with a high-yield period of 2-4 years.

4. Winter management: In early September, the greenhouse should be covered with film and straw mats. In winter, keep the greenhouse temperature at 15-28°C, light a fire to raise temperature when necessary, no smoke in the greenhouse, and require 8-10 hours of light per day; in winter, uncover the straw mats at 8 AM, ventilate from 10 AM to 1 PM, and cover the straw mats at 5 PM.