What to Do When the Leaves of a Rose Bush Turn Yellow from Bottom to Top
Rose leaves turning yellow from bottom to top is a common problem in maintenance, often indicating abnormal root absorption function. This article analyzes the causes from three core dimensions and provides solutions to help rose enthusiasts accurately locate the source of the problem, and visually grasp the key points of operation with accompanying illustrations.
Core Management Solutions for Rose Yellowing Leaves
Container Optimization Solution
Container-grown roses often turn yellow due to poor ventilation in the container. Plastic pots, because of their dense material, can easily cause root congestion, leading to oxygen deficiency and the yellowing of the bottom older leaves first. It is recommended to use earthenware or root control pots, whose porous structure can increase soil oxygen content by over 40%. When repotting, be sure to retain the protective soil around the roots to avoid damaging the fine roots.
Substrate Improvement Strategy
Compact soil is a hidden killer. When the substrate density is >1.3g/cm³, it affects root development. It is recommended to use a golden ratio of peat soil to perlite of 3:1, which has a porosity of over 35% and combines water retention and breathability. Every spring, it is necessary to replace the top 5cm of the substrate and add decomposed pine bark to enhance permeability.
Nutritional Supplement System
An imbalance of nitrogen, phosphorus, and potassium can cause systemic yellowing of leaves. When nitrogen is deficient, the older leaves turn yellow first, and when iron is deficient, the new leaves lose their green color. It is recommended to use slow-release fertilizer (NPK 20-20-20) as a base fertilizer and apply water-soluble fertilizer every 10 days during the growing period. In the early stages of yellowing leaves, foliar spray with chelated iron fertilizer (0.05% concentration) can significantly improve the condition after 3 treatments.
By optimizing the container, substrate, and nutrition, over 90% of the yellowing leaf issues in roses can be improved within 15-20 days. It is necessary to maintain proper ventilation in the environment and regularly test the soil EC value (suitable range 1.2-1.8mS/cm). Prevention is better than cure, which is the essence of rose maintenance.