What Causes Rose Leaves to Turn Yellow
Roses, as common ornamental plants in courtyards and balconies, exhibit yellowing leaves as the most typical problem during maintenance. When new leaves of roses wilt and old leaves turn yellow, it often indicates that the plant is in a sub-healthy state. This article will systematically analyze the three main causes of yellowing leaves in roses and provide corresponding rescue plans.
1.1 Identification of Waterlogging and Root Rot Symptoms
Waterlogged plants first show uniform yellowing of the lower leaves, with young leaves presenting a light green water-stained appearance. There is a dull sound when tapping the pot, and moss or white salt crystallization can be seen on the soil surface.
1.2 Scientific Water Control Plan
Adopt the "Three-look watering method": look at the soil layer (2cm dry), look at the leaves (no dew in the morning), and look at the season (5-7 days/time in spring and autumn). Combined with ceramic stones at the bottom and a breathable matrix with 30% coconut bran, the risk of waterlogging can be reduced.
Two, Nutritional Imbalance Leads to Yellowing
2.1 Identification of Deficiency Symptoms
Nitrogen deficiency manifests as yellowing of old leaves with green veins; iron deficiency causes yellowing of the leaf flesh of new leaves but green veins; overall yellowing leaves are often caused by a long-term lack of soil replacement leading to a deficiency of trace elements.
2.2 Precision Fertilization Strategy
Use 20-20-20 balanced fertilizer during the growing period and switch to high-phosphorus and potassium fertilizer during the bud formation period. Supplement with chelated iron water-soluble fertilizer monthly, and combine with the application of decomposed sheep manure organic fertilizer in spring and autumn to improve the soil.
Three, Abnormal Light Affects Metabolism
3.1 Light Environment Diagnostic Criteria
Plants with insufficient light have elongated stems and thin, pale leaves; strong light burn is manifested by brown scorch on the leaf edges and brown sunburn spots on the leaf surface. Ground-planted roses need to ensure 4 hours of direct sunlight per day, and pot-planted roses are recommended to be placed on east-west facing balconies.
3.2 Light Adjustment Techniques
Use shade nets to deal with strong summer light, and rotate the pots in winter to ensure even light exposure. Supplemental lights can be set to 2 hours each in the morning and evening during continuous rainy days, at a distance of 40cm from the plant.
By observing the characteristics of yellow leaves to locate the cause of the disease, combined with the diagnostic flow chart and treatment schedule provided in the article, most yellow leaf problems can be improved within 2-3 weeks. It is recommended to establish a maintenance log, record watering and fertilizing cycles, and combine monthly leaf surface cleaning, quarterly soil testing, and other preventive measures to keep roses in the best ornamental state.