Detailed Explanation of Key Pruning and Management Techniques for Cut Rose Flowers

To ensure high quality and high yield of cut roses, generally rooted cuttings are replaced every 3-4 years, and grafted seedlings every 5-6 years. In recent years, the cultivation of cut rose varieties has accelerated in replacement as market-popular varieties change. Rose branches of different varieties differ in leaf shape, axillary bud morphology, axillary bud growth rate and flower type. The bud at the tip of the branch develops into a flower bud and blooms earliest; the 1-6 axillary buds below the flower successively sprout new branches, which grow progressively longer, form flower buds and bloom; the flower branches formed by axillary buds at the base and middle of the branch differ little in quality, but the flowering time of flower branches from the middle to the base is successively delayed, and pruning can be carried out according to these characteristics to regulate the flowering period. Cut roses have the habit of continuous flowering, and the tips of most newly sprouted branches can bloom. Only branches with insufficient supply of temperature, light, nutrients, water, etc. will not bloom and form blind shoots. Within the suitable temperature range for growth and development, the corolla and petal number decrease as temperature rises, and cut flower quality declines accordingly; conversely, when temperature drops to the suitable range, the corolla and petal number increase and multiply, and cut flower quality improves accordingly.

Pruning of cut roses mainly adopts the methods of bending branches and cutting branches. According to the branching hierarchy of cut rose plants, cut rose plants are divided into primary, secondary and tertiary (or first, second and third order) branches. After seedling plants are bent, the basal shoots emerging from the plant base are called primary branches, the branches emerging from primary branches are called secondary branches, and the branches emerging from secondary branches are called tertiary branches. According to the function and use of cut rose plant branches, they are further divided into cut flower branches and nutrient branches. Branches to be cultivated for cut flowers are called cut flower branches; branches used as nutrients after branch-bending treatment on cut rose plants are called nutrient branches. A high-yield plant type for high-quality cut roses has 4-5 cut flower branches, 5-6 uniformly plump nutrient branches, and a plant height of 50-60 cm. According to the high-yield and high-quality cut flower plant type structure, gradually cultivate the plant type in stages and maintain a reasonable structure of the plant type. The cultivation techniques are as follows:

(1) Branch bending: The branch-pressing rope (iron wire or nylon line) is 25-30 cm from the seedlings, and is pulled tight and fixed with iron stakes or wooden stakes on both sides of the planting bed. Press all branches serving as nutrient branches under the branch-pressing rope. During the seedling stage, all flower heads are removed while leaves are retained; when branches reach 40-50 cm in length, press the branches down, taking care not to break them. Newly sprouted overly thin branches are pressed as nutrient branches; branches emerging from nutrient branches continue to be pressed. When pressing branches, note that plants and branches must not cross each other, and the number of bent branches should be appropriate to cover the bed surface, so that leaves can receive sufficient light. Branch bending can be carried out regardless of the four seasons or morning and evening, and is a routine task. Generally, branches are more brittle in the morning and prone to breaking when pressed, so try to keep them from breaking. In the branch-bending operation, use one hand to hold the part of the branch to be bent and the other hand to twist and bend it downward with force, pressing the branch under the branch-pressing rope; for thick branches, twist and bend the branch at 10 cm from the root and then press it down, taking care to use both hands when twisting to avoid breaking the branch.

(2) Branch pressing: The method of cultivating flowering plants during the seedling stage is mainly branch pressing, which facilitates rapid cultivation of the cut flower plant type. When branches are 40-50 cm tall, they can be pressed; press the branches down and remove all flower heads, and continue pressing newly sprouted branches from the pressed branches. After plants are pressed, basal shoots grow rapidly; thick basal shoots are used as cut flower branches, or after the basal shoots show buds, they can be cut back leaving 4-6 leaves as cut flower mother branches; thin basal shoots continue to be pressed as nutrient branches.

(3) Plant type cultivation at the early flowering stage: After the cultivation of flowering plants during the seedling stage, some plants begin to harvest cut flowers, and most plants send out a large number of new branches. During this period, the main focus is cultivating the plant type while also harvesting cut flowers. The method of plant type cultivation, that is, the cultivation of branches at all levels: for thick basal shoots, leave 25-30 cm (4-5 five-leaflet leaves) and pinch, cultivating them into primary branches of the plant; for branches emerging from primary branches, thick ones can be used as cut flowers, and thin weak ones can be pressed as nutrient branches; for cut flower branches sprouting from primary branches, when harvesting flowers, cut at 10-15 cm (1-2 five-leaflet leaves) to cultivate them as secondary branches; for branches emerging from secondary branches, strong ones can be used as cut flower branches, and thin weak ones are pressed as nutrient branches; when harvesting flowers, cut at 5-10 cm (1-2 leaves) to cultivate them as tertiary branches; generally, cultivating tertiary branches in cut rose plants can achieve a high-yield and high-quality plant type, and some cut rose plants can take shape after cultivating secondary branches. During plant type cultivation, it is very important to reasonably retain the height of branches at all levels, as they are closely related to the yield and quality of cut flowers. Generally, the stronger the branch, the higher the retained branch, and the more branches emerge after cutting, and the more branches reach the cut flower standard; conversely, the weaker the branch, the shorter the retained branch, and the fewer branches emerge after cutting, and even fewer reach the cut flower standard. If retained branches are too high, too many branches emerge, resulting in high yield but low quality; conversely, if retained branches are too low, yield is also relatively low. When there are too many nutrient branches, bottom branches or branches with pests and diseases should be gradually eliminated. Plants send out new basal shoots every year, and during the period when new basal shoots gradually rise, the original aged main branches should be eliminated.

(4) Pruning during the production flowering period: To ensure the quality and yield of exported cut roses, during the production flowering period, bent branches and cut flower branches are retained in a certain proportion. Generally, plants have 3-5 main cut flower branches, 5-6 uniformly plump nutrient branches, and a plant height of 50-60 cm. Plant type cultivation in winter is very important. Generally, starting in October each year, the plant height is gradually raised to form more flowering branches. After Valentine's Day flower cutting ends, the plants are retracted and pruned back to the normal cut flower height of 50-60 cm. During the production flowering period, new nutrient branches must be continuously bent and pressed, taking care not to break the nutrient branches, and crossing and overly dense branches should be cut off. After each cut flower peak, appropriately prune and tidy up; for new branches emerging from nutrient branches, retain part for flower production in winter and press the rest as nutrient branches. Diseased, pest-infested, withered, old and weak branches should be cut off in time, and side buds and lateral buds on cut flower branches should be removed in time. After the spring Valentine's Day flower production ends, cut off some aged main branches, and take care to cultivate basal shoots emerging from the base as new main flowering branches.