What Causes the Blackening of Jasmine Leaves?
Jasmine leaves are bright green and the flowers emit a fragrant aroma, making them a popular choice for indoor greenery. However, the issue of blackening leaves during maintenance has troubled many gardening enthusiasts. This article systematically analyzes the three core causes and combines practical solutions to help you accurately locate the root of the problem.
Analysis of the Main Causes of Black Jasmine Leaves
Imbalance in Water Management
The most common cause of blackening leaves is root suffocation. Jasmine roots require an alternating wet-dry breathing environment; excessive watering can create a waterlogging layer that blocks oxygen supply. Flooded plants first show wilted young leaves, followed by brown water-stained spots on the edges of older leaves, eventually turning completely black. It is recommended to use the bamboo skewer test: insert a 30cm bamboo skewer into the potting soil, then observe the moisture level after pulling it out; only water when the upper half of the skewer is dry.
Fungal Disease Attack
Leaf spot disease is the second leading cause of blackened jasmine leaves. The pathogen spreads through the air, initially appearing as pinpoint brown spots on the leaf's back, which expand to 1cm diameter circular spots within 3-5 days, with black sporulation on the surface. Special attention should be given: under high temperature and humidity, the disease spreads faster. Diseased leaves should be immediately pruned 1cm outside the healthy tissue with scissors sanitized with alcohol and sprayed with a 70% mancozeb solution diluted 800 times, for three consecutive treatments (every 5 days).
Malnutrition Supply Imbalance
Salinity damage caused by excessive fertilization is often overlooked. When the EC value of the potting soil exceeds 2.0mS/cm, jasmine plants show typical symptoms such as leaf tip burning and inward expansion. It is recommended to apply decomposed soybean cake water (diluted 1:50) monthly instead of chemical fertilizers, combined with foliar applications of 0.1% ferrous sulfate solution in spring and autumn. If fertilizer damage has already occurred, immediately flush the roots with water three times, with a 2-hour interval between each.
Systematic Maintenance Plan
To prevent blackening of jasmine leaves, a scientific maintenance system needs to be established: use red陶 pots to enhance breathability, and mix soil in the ratio of珍珠岩:腐叶土:蛭石=3:5:2. Regularly rotate the pot to ensure even light exposure, and maintain the optimal growth temperature of 18-28°C. When repotting in spring each year, soak the roots in a 1000-fold potassium permanganate solution for 20 minutes to effectively prevent diseases.
By accurately identifying the different symptoms of blackened leaves and combining them with corresponding treatment measures, jasmine plants can recover to a healthy state within 2-3 weeks. It is recommended to establish a maintenance log to record watering, fertilizing, and the occurrence of diseases and pests, gradually mastering the plant's growth patterns.