How to grow Rosa roxburghii? A detailed guide to cultivation methods

Rosa roxburghii, also known as cili, mulizi, cili fruit and so on, is a spreading shrub in the genus Rosa of the family Rosaceae. Its flowers are elegant, with a ring of golden-yellow anthers densely set among the pink petals, which is quite distinctive, and its yellow thorns are full of wild charm. It has high ornamental value and is suitable for mass planting for greening on slopes and roadsides, and is also used as a hedge material. Let us take a look at the cultivation methods for Rosa roxburghii!

Growth habits of Rosa roxburghii

Rosa roxburghii is distributed in Shaanxi, Gansu, Jiangxi, Anhui, Zhejiang, Fujian, Hunan, Hubei, Sichuan, Yunnan, Guizhou, Xizang and other places, and grows wild or is cultivated in various regions. It prefers a warm, humid environment with ample sunlight, has strong adaptability, is relatively cold-tolerant and slightly shade-tolerant, and is not strict about soil requirements, though fertile sandy loam is best.

Propagation methods for Rosa roxburghii

1. Sowing: Rosa roxburghii seeds are usually collected in September and can be sown in autumn or stored in sand until spring sowing the following year, generally germinating 20 to 25 days after sowing. The seeds can be used for raising seedlings, but because seedlings grown from seed are difficult to keep alive, it is generally not recommended to use seeds for propagation. In production, softwood cuttings from the current year are mostly used for raising seedlings, as they root easily. Rare and valuable varieties are more difficult to propagate by cuttings.

2. Cuttings: Rosa roxburghii cuttings can be taken in early spring or during the plum rain season. Softwood cuttings from the current year root easily when used for raising seedlings. After cutting, be sure to keep the cutting medium moist, but do not let it become too wet, otherwise it will cause rot. At the same time, attention should also be paid to air humidity; plastic film can be used to cover and maintain humidity, but be sure to ventilate within a certain period.

Cultivation methods for Rosa roxburghii

1. Light: Rosa roxburghii likes a warm environment with ample sunlight and can tolerate cold and shade, so when growing Rosa roxburghii, give it sufficient light and maintain a suitable growing temperature.

2. Watering: During care, Rosa roxburghii needs to be kept adequately supplied with water, but note that sufficient water should be given during summer droughts. During the flowering period, water supply must also be adequate so that it can bloom abundantly and beautifully. In the rainy season, take care to do good drainage work and avoid waterlogging, so as to prevent the roots and stems from rotting.

3. Fertilizing: To keep Rosa roxburghii growing healthily, adequate fertilizer and water must be ensured. During the comfortable growing period, fertilize frequently, once a month. When the temperature is high and it is relatively dry, some light fertilizer can be applied; reduce fertilizing in winter. In addition, after flowering, apply a quick-acting fertilizer once or twice.

4. Pruning: Pruning is essential. Whether it is cutting back overlong branches, overly dense branches, dead branches, diseased branches, or spent flowers and excess buds, it is all very necessary. Pruning can make the plant shape of Rosa roxburghii attractive and help with ventilation and light penetration, enabling the plant to grow and develop better, reducing the chance of some pests and diseases, and lowering nutrient consumption so it blooms better.

Pest and disease control for Rosa roxburghii

1. Powdery mildew: Leaves, petioles, young shoots and flower buds can all be affected. In the early stage of the disease, spray 20% triadimefon emulsifiable concentrate at 1000 times dilution, or 20% triadimefon-sulfur suspension concentrate at 1000 times dilution, or 50% carbendazim wettable powder at 800 times dilution. If resistance to the above fungicides develops, switch to spraying 12.5% myclobutanil emulsifiable concentrate or 30% triflumizole wettable powder at 3000 times dilution. Before bud break in early spring, spray lime sulfur mixture at 2 to 3 degrees Baume or 45% crystalline lime sulfur at 40 to 50 times dilution to kill overwintering pathogens.

2. Black spot: Black spot mainly attacks the leaves, petioles and young shoots of Rosa roxburghii. When the leaves first become diseased, small purplish-brown to brown spots appear on the upper surface, and after enlarging they are mostly round or irregular dark brown lesions. When Rosa roxburghii develops black spot, spray carbendazim, thiophanate-methyl, daconil and other chemicals.

3. Anthracnose: Anthracnose mostly occurs sporadically and can be controlled at the same time when controlling black spot and leaf spot. In late autumn and early winter, clean the garden in time and collect diseased fallen leaves to burn in a concentrated way. Strengthen care, prune appropriately, and thin out overly dense branches so that ventilation and light penetration are good. When necessary, spray 20% longkejun suspension concentrate at 500 times dilution, or 78% kebo wettable powder at 600 times dilution, or 75% daconil wettable powder at 600 times dilution, or 50% shibaogong or shibaike wettable powder at 1000 times dilution, or 25% tanteling wettable powder at 500 times dilution.

4. Scarab beetles: Scarab beetles mainly harm the roots, leaves, flower buds and other parts, seriously affecting flower yield and quality. Use light traps, willow and poplar traps, shaking to capture and kill, and so on. When the damage is severe, spray 2.5% deltamethrin at 2000 to 3000 times dilution or 50% phoxim at 1000 to 1500 times dilution. The results are both fairly good, but spraying must never be done during the flowering period.

5. Leaf rust: Leaf rust is a common disease of Rosa roxburghii, and both leaves and new branches may become diseased. Severe cases can cause large areas of leaves to drop, causing the flowers to lose their ornamental value and even die. If this disease is found, deal with it promptly. Spray triadimefon at 800 times dilution on the foliage once a week for 3 to 4 consecutive times, and the disease can basically be cured.