Causes and treatment methods for yellow leaves of plum blossoms
Every winter on the twelfth lunar month, the scenery of plum blossoms blooming in the cold is always fascinating. However, the yellow leaf phenomenon that appears during the maintenance process has confused many gardening enthusiasts. This article will deeply analyze the three main reasons for the yellow leaves of plum blossoms, and provide scientific and systematic solutions to help you reproduce the heroic posture of plum blossoms. 1. Nutritional imbalance causes yellow leaves 1.1 The harm of excessive fertilization. Plum blossoms are barren tolerant plants. They can meet their needs by applying diluted organic fertilizer every 14 days in spring and autumn. Excessive fertilization (especially nitrogen fertilizer) will lead to an increase in soil EC values and an imbalance in osmotic pressure in the roots, which is manifested by scorched leaf edges and yellowing between veins. Fertilizing during winter dormant periods is more likely to cause fertilizer damage, which causes soil hardening and affects air permeability. 1.2 Scientific fertilization plans should immediately use siphon method to wash the substrate 3-5 times after discovering fertilizer damage. It is recommended to adopt the principle of "thin fertilizer and frequent application", use special slow-release fertilizer for plum blossoms (NPK5 -10-5) combined with decomposed sheep manure, and apply top fertilizer once during spring germination and flower bud differentiation periods. The soil conductivity is regularly monitored through an EC test pen to keep the value within the range of 0.8- 1.2 mS/cm. 2. Key points of water management 2.1 Diagnosis of stagnant water and rotten roots. Plum blossoms have extremely low tolerance to stagnant water. When new leaves are yellowed and old leaves fall off, and brown water spots appear at the base of the stem, it can be determined as waterlogging. At this time, the oxygen content of the soil is less than 5%, and the roots undergo anaerobic respiration to produce toxic substances such as ethanol. 2.2 The precision irrigation strategy adopts the "see dry, see wet" method, and wait until 2 cm of topsoil is dry before irrigating thoroughly. In the rainy season, the flowerpot should be tilted 15° to promote drainage. It is recommended to use ceramite cushion + red jade soil (accounting for 30%) to improve the substrate. Smart soil hygrometers can help monitor water content and maintain substrate humidity at 40- 60% RH. 3. Optimization plan for the light environment 3.1 Regulation of light intensity requires 4-6 hours to scatter light per day. Direct light (>80000lux) will cause photooxidative damage, which is manifested as yellowing and curling of leaves. Long-term shading (<10000lux) affects anthocyanin synthesis, and new leaves appear morbid yellow-green. 3.2 Light management practices recommend using sunshade nets to adjust light, block 30%-50% of strong light in summer, and maintain it in full sunshine in winter. Regularly rotate the flowerpot to ensure uniform light reception, and cooperate with a fill light (spectrum 400- 700nm) to fill light for 2 hours every day on continuous rainy days. Appropriate enhancement of light after falling leaves can promote flower bud differentiation.
By accurately controlling the three major factors of water, fertilizer and light, combined with regular pruning (retaining 2/3 of healthy branches) and pest prevention (spraying lime sulfur mixture in early spring), plum blossoms can be kept healthy. It is recommended to test the SPAD value of the leaves every month, and adjust the maintenance plan in time when the chlorophyll content is lower than 35, so that your plum blossoms bloom year after year.