Open-field Cultivation Methods and Technical Key Points for Tea Rose

The tea rose is a plant of the genus Rosa, suitable for growing in environments with ample sunlight and good air circulation. It is not demanding regarding soil, but the following aspects should be noted in open-field cultivation.

1. Cultivation site. The tea rose is a light-loving plant, so a sunny location should be chosen during cultivation, avoiding planting beside tall buildings, under tree shade, or on the shady side of hillsides. The ideal soil for cultivating tea roses should have good granular structure and be rich in organic matter. The tea rose is not demanding regarding soil pH and can grow in soil with a pH of 5.5-8.0, but grows best in slightly acidic soil with a pH of 6. Most of the tea rose's root system is concentrated in the top 30 cm-40 cm of soil, so the depth of the tillage layer should be 50 cm-60 cm.

2. Fertilizer selection. The tea rose likes fertilizer, especially organic fertilizer such as manure and compost. The application rate of organic fertilizer is about 150 kg per 10 plants. The tea rose has a long flowering period, so during its growth, chemical fertilizer should be applied as a top dressing for quick effect. The nitrogen, phosphorus and potassium ratio of the top dressing should be 1:1:2 or 1:2:3. The commonly used chemical fertilizer is superphosphate, applied at an average of 2 kg per 100 sq m.

3. Planting spacing. The plant and row spacing for tea rose cultivation varies according to the purpose of cultivation. For variety nurseries used for breeding or scientific research, the commonly adopted plant and row spacing is 150 cm x 80 cm; for landscaping in parks, flower shops, streets, factories and mines, it should be adapted to local conditions with wider row spacing. Before planting, the seedlings should be pruned once, cutting off damaged branches, diseased branches and weak branches; damaged or overly long roots should also be cut off. The soil moisture at planting should be appropriate. If too wet, planting should be postponed, and the soil should be dried in the sun for a few days before transplanting; if too dry, a thorough watering should be given 2-3 days in advance.

4. Water management. Water management for tea roses is also an important task. Insufficient or excessive water will inhibit their growth and development, so it needs to be adjusted according to their different growth and development stages. Spring and autumn are the peak flowering periods of tea roses, and during this time the water supply should be sufficient; before pruning the tea rose plants, watering should be suspended to control plant growth, and after pruning the amount of watering should be appropriately increased. In addition, if cultivating in sandy soil with poor water retention, the frequency of watering should be appropriately increased; in soil with poor drainage, watering should be done cautiously to prevent root rot.

5. Pruning and shaping. Pruning is done to allow the tea rose to sprout as many strong branches as possible, thereby improving flower quality. In addition, pruning can also make the tree shape complete and balanced, harmonising it with the space in which it lives. The most suitable time for pruning is when the plant stops dormancy and is about to sprout, or when it stops growing and is approaching dormancy. There are 3 forms of pruning: light pruning, moderate pruning and heavy pruning. Light pruning means cutting back healthy branches and removing inward-growing buds; moderate pruning means cutting off the previous year's healthy branches at the base or cutting off half; heavy pruning means keeping only 3-4 previous-year branches on the whole plant, then cutting back 20 cm above ground level. For newly transplanted plants, if they have already been pruned before planting, no further pruning is needed in the first year of planting. After one year, thin and crossing branches can be cut off at the base, and at least half the length of the retained strong branches should be cut off. Tea roses planted for more than 3 years still need annual pruning to maintain a perfect plant shape.

6. Winter care. In areas where the minimum winter temperature is below minus 15°C, some anti-freezing measures should be taken. For example, pile 20 cm of soil at the base of the plant, or wrap the plant clump with straw curtains, gunny bags, plastic film, etc. In areas where the minimum winter temperature reaches minus 20°C, it is necessary to loosen the soil on one side of the plant, lay the plant down and cover it entirely with soil.