Deer are known to eat the foliage and blooms of this type of rose bush, so it is important to protect the plant. Aphids, spider mites, powdery mildew, and black spot may also cause damage. Overly humid or wet conditions can result in fungal diseases.
Light
Rosa chinensis plants thrive in full sun but can tolerate filtered shade. For the best growing results and bloom, choose a location with at least 6 hours of sunlight.
Soil
These roses prefer loamy, sandy, well-draining soil that stays consistently moist. However, they are tolerant of many garden soil conditions and can be grown even in heavy soils, as long as water drains away. They do not tolerate soggy, wet soil. Neutral pH levels of 6.0 to 6.9 are ideal, although this rose variety can also be grown in soil that is slightly acidic to slightly alkaline.
Water
Water regularly but avoid over-saturating the soil. It’s best not to allow the soil to dry out completely. Check the first few inches of the soil to gauge its moisture level. If the first few inches begin to feel dry, it is time to water this rose. How often you need to water depends on your location, rainfall, and the time of year. Rosa chinensis needs more frequent watering while in bloom.
Temperature and Humidity
This hardy rose variety can be grown in zones 6 to 9, and is tolerant of a wide range of temperatures. Temperatures dipping below 40 or reaching above 90 degrees Fahrenheit will cause this rose to go dormant. As for humidity, it does well in moderate humidity levels. If humidity is too high, the flower petals may stick together. High humidity levels can also lead to moisture-related diseases.
Fertilizer
For a good start, add compost or fertilizer to well-worked soil before planting to give the rose all the nutrients it needs. Fertilize established roses monthly during the growing season. Use a gentle, slow-release fertilizer so as not to over-fertilize.
Types of Rosa Chinensis
R. chinensis var. chinensis: This variety is known for its hardy nature, bushing or climbing habit, and deep red, pink, or white blossoms that appear in clusters. R. chinensis var. spontanea: This variety is very similar in appearance to var. chinensis with red to pink flowers, but has a less tidy appearance and a more look as it climbs nearby objects for support. The small, flat or slightly cupped flowers usually appear solitary, not in clusters. R. chinensis var. semperflorens (Curtis) Koehne: This hardy variety, too, is similar in appearance to var. chinensis. Where it shines is in the blooms, which are deep red and semi-double to double. Flowers appears as solitary blooms or in clusters of two or three.
Pruning
Proper annual pruning of a rose bush is necessary for healthy, full growth. This is best done in the late winter or early spring. For roses kept as vines, keep the main branches long and prune away other branches to allow for proper airflow. For bushes, trim away any crossing branches or areas that are dying. Then prune the bush back to about one-third of its size.
Propagating Rosa Chinensis
Rosa Chinensis can be propagated through cuttings, divisions, and grafting. Cuttings and divisions are more common and can be done without a rootstock plant. Grafting requires a rootstock plant. To propagate through cuttings, you need a sharp pair of snips, a pot, well-draining, rich soil, a plastic bag, and a clean stick. Then follow these instructions: To propagate through divisions, you need a shovel, sharp garden snips, and a pair of garden gloves. Then follow these instructions:
Potting and Repotting Rosa Chinensis
Rosa chinensis does well in the ground, but can also be grown in pots. Be sure to select a large pot to allow the root system to branch out and thrive. One with adequate drainage holes is also very important, as these roses cannot tolerate soggy soil. If the rose bush outgrows its container, it is best to repot in the early spring or late fall while the plant is dormant. Wearing protective gloves, tilt the pot on its side and tap it to loosen the root structure. Slide the rose out and plant it in a larger pot with fresh soil.
Overwintering
For areas where frost occurs in the winter months, it is best to protect Rosa chinensis to prevent damage. Wrap the bush in horticultural fleece. Alternatively, create a collar around the trunk with fencing, then fill the space with leaves or straw to create a layer of insulation. Add a layer of mulch on the ground to help insulate the roots.
How to Get Rosa Chinensis to Bloom
Rosa chinensis plants are prized for their long bloom season with lovely red, pink, or white flowers. The flowers are single or semi-double with a light, sweet aroma. Trim away faded flowers to encourage more flowering. During the blooming period, apply a light fertilizer monthly and make sure the rose receives plenty of sunlight, since too little light will reduce the number of flowers.
Common Problems With Rosa Chinensis
Rosa chinensis may present the gardener with problems if the growing conditions are not ideal. Here are some common problems you may encounter.
No Blooms
A rose bush that is not flowering is signaling conditions inadequate for flower production. For Rosa chinensis this happens when the plant is not receiving enough light. Try moving it to an area that gets more sun daily. If the plant is receiving sun but is still not blooming, it could be due to nutrient deficiency. A monthly application of fertilizer during the growing season can correct this problem.
Yellowing Leaves
Rosa chinensis foliage can turn yellow for multiple reasons. If the foliage is yellow and dry, the leaves could be getting burned by too much direct sunlight. Potted rose bushes can simply be moved to areas where there’s less direct sunlight, while in-ground rose bushes may require a shade cloth. If the leaves are yellow and limp and the soil is excessively moist, this is a sign the rose is receiving too much water. Cut back on water and loosen the soil to help the water drain through. Add sand or another fast-draining material to increase drainage. Lastly, yellowing foliage could be caused by too much fertilizer. If this is the case, rinse the soil thoroughly to remove excess fertilizer and withhold fertilizer until the plant recovers. If there is a large buildup of fertilizer, you may need to replant in fresh soil.
