How to Grow Rosa roxburghii? A Detailed Guide to the Latest Planting Techniques and Methods
Rosa roxburghii, also known as ci suan li zi, mu li zi, ci mei guo, etc., is the fruit of the perennial deciduous shrub Rosa roxburghii in the Rosaceae family. It prefers a warm and humid climate, and can be planted in areas with an average annual temperature of 12-16°C and annual rainfall of more than 1000 mm. It has low soil requirements and prefers acidic or slightly acidic soil with a pH of 5.5-7. Now let us take a look at the planting techniques for Rosa roxburghii!
Propagation Methods for Rosa roxburghii
1. Seed propagation: divided into spring sowing and autumn sowing. Rosa roxburghii seeds have no obvious dormancy period. If sown immediately after the seeds mature in autumn, the germination rate and seedling emergence rate can reach more than 90%. For autumn sowing, collect seeds after the fruit matures in early to mid-September and sow them immediately in the seedbed; seedlings emerge in mid to late October. Transplant them to the nursery in March of the following year, and they can be ready for outplanting by the end of the year. However, in areas with severe winter cold, plastic film covering is needed to prevent freezing. Spring sowing is best from late February to early March; seedlings emerge in early April and are transplanted to the nursery from late May to early June. The day before sowing, place the seeds in warm water at 50-60°C and soak for 12-24 hours. After removing them, wash them clean and sow, which can advance germination by 5 days and increase the germination rate.
2. Cutting propagation: can be carried out in spring, summer and autumn. For spring cuttings, cut the 1-year-old branches pruned in winter into 10-12 cm lengths, with the lower end cut diagonally below a bud and the upper end cut diagonally 1 cm above a bud. Store them in wet sand in bundles of 100. In early to mid-February of the following year, insert them diagonally in the nursery at a plant-row spacing of 9x24 cm, leaving 1 bud exposed, and firm the bed soil around the cuttings. They sprout in mid-March, with a survival rate of more than 90%. For summer and autumn cuttings, take 1-3-year-old branches and treat the base of the cuttings with ABT rooting powder; the rooting survival rate is 100%.
Planting Methods for Rosa roxburghii
1. Planting preparation: Before planting, the soil should be deeply plowed, matured, improved, and planting trenches or holes should be dug. When establishing an orchard on mountainous land, the soil plow layer is thin, organic matter is low, and fertility is poor, so soil improvement is needed. Before planting, generally dig trenches or holes 40 cm deep and 60 cm wide or in diameter, thoroughly mix the topsoil with farmyard manure and backfill, and settle it with water or firm it while filling.
2. Planting density: For plots with poor site conditions or extensive management, a row-plant spacing of 2 m × 1 m or 2 m × 1.5 m can be used. For plots with fertile soil and sufficient rainfall, the row-plant spacing can be appropriately larger, with 2.5 m × 1.5 m or 2.0 m × 1.5 m being more suitable.
3. Planting time: Because Rosa roxburghii likes humidity and is not tolerant of drought, and its protective tissues are not well developed, it is prone to transpiration water loss. Therefore, in Guizhou, planting is generally carried out from late November to early February of the following year during the dormant period after leaf fall. In other areas, it can be determined as appropriate according to actual conditions.
4. Planting method: When planting, first dig a pit of suitable size in the planting hole, place the Rosa roxburghii seedling into the pit, determine the position and depth of the seedling, spread the root system, fill in fine soil, then lift the seedling slightly upward so that its root system spreads out, and then fill the soil back and firm it. The planting depth should be based on the soil burial depth when the seedling leaves the nursery. Build small soil ridges around the planting hole or on both sides of the trench, water thoroughly after planting, and strengthen management to ensure survival.
Planting Management of Rosa roxburghii
1. Training and pruning: Maintain a tree height of 1.5-2 m and a crown width of about 1.5 m, with 5-8 main branches in the whole clump, on which fruiting mother branches are distributed alternately. In the early stage after planting, let them grow freely to promote fruiting and form a tree crown, then thin out overly dense, drooping and overly long branches, and adopt a combination of winter and summer pruning to cultivate fruiting mother branches, so as to achieve the goal of three-dimensional fruiting.
2. Fertilizer and water management
① Adjusting pH: Adjust the soil pH so that it is slightly acidic to neutral, pH 5.5-7.0. If the soil is too acidic, increase the application of lime water to adjust it; if the soil is too alkaline, increase the application of gypsum or sulfur.
② Increasing organic fertilizer application: Increase the application of organic fertilizers, such as barnyard manure and miscellaneous soil manure. Apply base fertilizer in autumn every year at 22500 kg per hectare. Apply topdressing once each before flowering and during the young fruit stage, with 75-90 kg of urea per hectare.
③ Soil moisture management: Strengthen soil moisture management. Irrigate in time during drought, drain in time during waterlogging, and carry out timely intertillage and weeding when the soil becomes compacted, and so on.
3. Pest and disease control: Common pests and diseases of Rosa roxburghii include powdery mildew, aphids, nettle caterpillars, bagworms, citrus spiny whitefly and fruit borers. Powdery mildew occurs in both spring and autumn. In early June, at the initial stage of the disease, spray triadimefon in time, with a control effect of up to 74%-88%. Aphids mainly damage new shoots. Spraying 80% dichlorvos 2000-fold solution is effective, and it is also effective against leafhoppers, nettle caterpillars, tortrix moths, and small leaf beetles. Citrus spiny whitefly parasitizes on the underside of leaves. When pest damage occurs from May to August, 2000-fold isocarbophos can be used for control. Spraying 2.5% deltamethrin 6000-fold solution twice consecutively from early July to August can control fruit borers.
4. Harvesting and drying: Fruits mature successively from August to the end of September. It is best to pick them in batches when the fruit is deep yellow and gives off a fruity aroma. Handle gently during picking to prevent compression, and sell immediately after picking. Dry fruit processing is simple: just sun-dry or oven-dry the fruit. The storage time of dried products is about 1 year. Before storage, fumigate each ton of dried product with 2 kg of sulfur powder for 2 hours, then pack it in hemp bags and store it with an outer film bag. After 1 year, vitamin C loss is only 2.85%. If not fumigated with sulfur, vitamin C loss after 1 year can be as high as 80%.