Reasons and Solutions for the Yellowing of Roses in Summer
Share some knowledge about why roses turn yellow in summer and how to solve the problem. Please refer to the detailed introduction below.
Reasons and Solutions for the Yellowing of Roses in Summer
Many rose enthusiasts have noticed an increasing number of yellow leaves on their roses as summer begins. Just yesterday, they picked off yellow leaves, and today, new ones have appeared. For新手 gardeners, this situation can be quite unsettling. What's happening? What should they do?
Reasons and Treatment for Yellowing of Roses in Summer
After summer begins, temperatures gradually rise, and the sun becomes stronger. If your roses are still managed in the same way as before, they are likely to develop yellow leaves due to the following four reasons.
1. Sun Exposure Accelerates Old Leaf Metabolism
If there are many old leaves at the bottom of your rose plant, as temperatures rise and rainfall increases in summer, the old leaves at the bottom of the rose plant are prone to yellowing and falling off due to high temperature and humidity.
This is actually a normal phenomenon of leaf metabolism, which is influenced by temperature and humidity, accelerating the metabolism of old leaves. When this kind of bottom or inner old leaves turn yellow, they should be removed as soon as possible. After removal, the plant will have better ventilation, and the chance of pest and disease infection will decrease.
2. Acute and Chronic Yellowing Caused by Drought
After summer begins, the dry-wet cycle of potting soil accelerates significantly. What used to require watering every three days might now need daily watering. If watering is not adjusted in time, it can easily lead to drought and yellowing of rose seedlings.
Acute drought can cause leaves to lose water and wilt, which is easy to spot. However, after watering, a large number of yellow leaves or dry leaf tips may gradually appear the next or the third day. This is a后遗症 of acute drought, which is actually a symptom of damage to the rose's fine roots.
Rose plants that have suffered from acute drought require more careful management afterward. Do not blindly increase watering amounts; instead, adhere to the principle of watering when the soil is dry and after it has absorbed the water. Adding a bit of root stimulator or vitality enhancer to the water can promote the growth of new roots and help the plant recover quickly.
Compared to acute drought, chronic drought is often not easily detected, especially by新手 gardeners, who cannot believe that their roses are suffering from drought, as they water every day.
Note that watering every day does not mean that the potted rose plant will not be affected by drought. There are two situations that need attention.
① Small pots or rose plants with roots fully grown
If there are many branches and leaves on your rose plant but the pot is relatively small, even daily watering may not be enough for the rose to consume, leading to chronic drought and frequent yellowing of leaves, making the plant look dry and not lively.
Also, if the pot has not been repotted for a long time and the roots have filled the pot, the soil has been almost consumed by the roots, and the water poured in cannot be retained.
For these two situations, it is necessary to change to a larger pot in time to ensure sufficient fertilizer and water. But be careful, changing pots in summer is not the same as in autumn and winter. In summer, you must change pots with the original soil ball, or it may easily rot.
② Excessive drought of potting soil
If the potting soil of a potted rose is too dry, it can be difficult to water thoroughly. When the matrix is too dry, it becomes hydrophobic, and the water we pour will flow directly through the gaps instead of being absorbed and stored by the matrix. In this case, although a lot of water flows out from the bottom of the pot, the potting soil is still dry.
In this situation, even if you water every day, the potting soil is still relatively dry and lacks water. When the potting soil is too dry, it is recommended to use the immersion method to thoroughly soak the soil, and then water according to the principle of "watering when dry and after absorption."
For specific operations and techniques on watering potted roses, you can refer to the book "How to Start and Bloom Roses from Scratch." Proper watering can make your gardening journey much smoother.
3. Leaf Burn Caused by Fertilizer or Pesticide Damage
Also, during the summer, fertilizing and spraying pesticides need to be done with extra care. High fertilizer concentrations can easily cause fertilizer damage, or incorrect timing of fertilizing or spraying can easily cause leaf burn.
Whether fertilizing or spraying, it is recommended to avoid the high-temperature period of noon and do it in the evening when the temperature is lower, which is conducive to the roses' dilution and less likely to cause burns.
The issue of fertilizing roses in the summer will be introduced in tomorrow's article. Stay tuned.
4. Leaf Yellowing and Falling off Due to Diseases and Pests
Lastly, it is necessary to mention that diseases and pests, such as black spot and spider mites, are the two biggest killers for roses in summer.
Black spot can cause rose leaves to turn yellow and fall off until they become "bare sticks," while spider mites will make your rose leaves "empty on the surface."
Do you think the rose above is still relatively healthy? In fact, this rose has already been infected with spider mites. A close look at the leaves will reveal dense pinprick-like yellow spots caused by spider mites.
Spider mites absorb sap, causing the leaves of the rose to lose their original function. As spider mites increase, the entire plant will eventually wither and die from being "sucked dry."
Black spot and spider mites require prevention, early detection, and treatment. Physical prevention is relatively difficult, and daily management needs a combination of physical and chemical control methods, maintaining good ventilation and proper humidity, and坚持 drug prevention every 10 days or so. The drug prevention can refer to the comprehensive control methods in the book "How to Start and Bloom Roses from Scratch."
Do you understand the detailed introduction about the reasons and solutions for the yellowing of roses in summer?