Analysis of Common Manifestations and Specific Causes of Abnormal Growth in New Leaves of Chinese Roses
Let's take a look at the possible reasons for the abnormal growth in Chinese roses together.
Recently, in the iAsk circle, there has been a significant increase in consultations regarding the abnormal growth of rose leaves. Similar consultations are often seen, indicating that the abnormal growth of rose leaves is a relatively common phenomenon recently. Today, I would like to share my views on this issue.
Possible Reasons for Abnormal Growth in Chinese Roses
Many hobbyists believe that the abnormal growth of new leaves and buds in Chinese roses is caused by thrips, but the thrips insects say, "Why am I always being blamed?"
Indeed, this symptom is very similar to the damage caused by thrips, but when looking for the root cause of a problem, we cannot just look at the surface phenomena. This point has been emphasized in the book "How to Successfully Care for Flowers from Scratch."
When a plant has a problem, we need to look for the root cause from different directions, identify the possible reasons based on the symptoms, and then analyze and judge specifically based on the care history.
For example, this obvious issue of new leaf scars and abnormalities could be caused by thrips damage, or it could also be caused by excessive fertilization or pesticide use. To make a specific distinction, we need to consider our own care environment and management practices.
For instance, it is currently early spring, and in most regions, there is no significant damage from thrips yet. The damage caused by thrips mainly starts from summer. Therefore, in the early spring stage, when there are few diseases and pests, thrips can probably be ruled out, except for southern regions.
After ruling out the possibility of thrips, we should continue to investigate the care issues. Reflecting on the recent management, including fertilization and pesticide applications, such as fast-acting fertilizer for root irrigation, foliar spray, buried organic fertilizer, and even the base fertilizer added during the potting in winter, all need to be considered.
Analysis of Common Manifestations and Specific Causes of Abnormal Growth in New Leaves of Chinese Roses
1. -- Abnormal Growth of New Leaves Caused by Thrips Damage --
The abnormal growth of new leaves caused by thrips usually manifests as brown scars on the back of the leaves,畸形 new leaves, or blackened new buds that do not sprout, with the damage occurring from summer to autumn.
Thrips not only damage the tender leaves and buds of Chinese roses but also harm the flower buds and old leaves. When the flower buds and old leaves are damaged, they usually show brown scars. The tender leaves and buds mostly show abnormalities and萎缩.
In early spring, the focus for preventing pest damage in Chinese roses is mainly on aphids, and the medicine used to prevent aphids can also kill thrips. Since the number of thrips in spring is relatively low, and aphid prevention medicine is frequently sprayed, thrips do not show significant damage. However, it is important to take preventive measures in summer, and it is recommended to alternate the application of dinotefuran, acetamiprid, and pyrethroids every 10-15 days.
2. -- Abnormal Growth of New Leaves Caused by Over-fertilization --
When repotting Chinese roses in winter, a large amount of organic fertilizer or slow-release fertilizer is often added as a base fertilizer, and some hobbyists even add compound fertilizers or other fertilizers as a base.
Personally, I recommend choosing fertilizers with long-lasting and gentle effects, such as well-fermented organic fertilizers and controlled-release fertilizers, while avoiding water-soluble fertilizers as a base fertilizer. Improper use can easily cause the Chinese roses to blacken and die.
Analysis of Common Manifestations and Specific Causes of Abnormal Growth in New Leaves of Chinese Roses
usually, the damage caused by over-fertilization can be seen when the Chinese roses just sprout. For example, the new buds are already abnormal, some have no leaves at the base, just a cluster of thorny leaves, and some new leaves are incomplete and have a very shiny appearance.
These two manifestations are common symptoms of over-fertilization caused by improper use of base fertilizer. The difference in the manifestation on new leaves is due to the varying degrees of root damage caused by the fertilizer.
The method of dealing with it depends on the severity. If only the new leaves are abnormal but the overall leaf color is shiny, no treatment is needed, as the new leaves will gradually become normal as the Chinese roses grow. For severe plants where the new leaves cannot unfold properly, it is recommended to retain the protective soil and change the soil.
3. -- Abnormal Growth of New Leaves Caused by Fast-acting Fertilizer --
The abnormal growth of new leaves caused by fast-acting fertilizer is most evident 3-5 days after applying the fertilizer, with the new leaves showing the most significant symptoms, while the previously grown leaves mostly show normal growth or partial fertilizer damage.
Usually, when the concentration of fast-acting fertilizer for root irrigation or foliar spray is high, or when the frequency of top-dressing is dense, this problem is more likely to occur. Especially for varieties with low fertilizer tolerance, when other varieties show normal growth, the varieties with low fertilizer tolerance are more likely to show fertilizer damage symptoms of abnormal new leaves. Attention should be paid to observe the fertilizer tolerance of each Chinese rose when fertilizing and reduce the amount appropriately for varieties with low fertilizer tolerance.
4. -- Abnormal Scars Caused by Over-concentration of Pesticide Spraying --
Chinese roses often need to be sprayed with pesticides to prevent and control diseases and pests, and many pesticide instructions are measured in mu, which causes many hobbyists to be unsure how to convert, often resulting in a higher concentration of pesticides. Within three to five days of spraying, new leaves of Chinese roses may show faded scars and may be accompanied by symptoms of wrinkled and deformed new leaves.
When preparing pesticides, if encountering mu dosage, I usually calculate 15-20 liters of water per mu. If the amount of pesticide per mu is small, I calculate 20 liters of water, and if the amount is more, I calculate 15 liters of water. Of course, this variable control still needs to be adjusted based on the application effect and accumulated experience.
Also, when spraying pesticides, it is quite particular. In the book "How to Grow Chinese Roses from Scratch," it is emphasized that when spraying pesticides, do not spray back and forth repeatedly, but rather spray evenly.
The above is the complete introduction of the possible reasons for the abnormal growth of Chinese roses and the common manifestations and specific causes of abnormal growth in new leaves of Chinese roses, hoping to provide you with help. Don't forget to visit GreenPlantNet for more flower care experience and knowledge!