Table of Contents
What Is Leaf Scorch?
Leaf scorch is a physiological condition that affects plants due to several unsuitable environmental factors, such as high temperatures, dry winds, and low soil moisture.
It commonly appears during July and August each year as discolored tissue along the leaf edges, between veins, and across leaf surfaces.
Leaves are the first part of the plant to show symptoms, and in severe cases, the entire leaf turns brown and eventually falls off.
Young trees are generally more vulnerable to leaf scorch than mature, vigorous trees.
Main Causes of Leaf Scorch in Plants
Water moves from the fine feeder roots through the trunk, branches, and stems until it reaches the leaves.
Any disruption in this natural water movement leads to leaf scorch. Below are the most common causes:
1. Root Problems
Several issues affecting plant roots can impede water movement and result in leaf scorch, including:
- Improper planting techniques that damage or kill the roots.
- Overwatering or underwatering, which suffocates the roots.
- Construction or building expansion that physically harms the roots and cuts off water flow.
- Planting with a large root ball, causing root suffocation.
- Soil erosion that exposes the roots.
- Excess moisture that prevents the growth of new roots.
- Cold temperatures that kill roots.
- High salt levels that damage root tissues.
2. Problems in the Trunk, Branches, and Stems
Issues affecting the above-ground parts of the plant also contribute to leaf scorch, such as:
- Mechanical injuries from lawnmowers and weed trimmers.
- Winter injuries and frost damage such as dieback and bark splitting.
- Damage caused by herbicides, especially from overuse or incorrect application.
- Diseases such as cankers and vascular wilts.
- Injuries from ties, wires, or cords used during plant support or care.
3. Leaf-Related Problems
Several environmental and care-related factors directly affect the leaves:
Environmental Conditions
- Excessively high temperatures
- Direct exposure to intense sunlight
- Reflective heat and radiation
- Strong, dry winds
Fertilizers
Incorrect or excessive fertilizer application is one of the major causes of leaf scorch.
Fertilizers contain salts that draw moisture out of the leaves, leading to burned edges and even plant death.
Chemical Exposure
Frequent use of household insecticides or chemical cleaners can cause leaf scorch in some plants.
Watering Issues
Irregular or insufficient watering and low humidity contribute greatly to leaf scorch, especially in tropical plants that cannot tolerate dry environments.
Secondary Causes of Leaf Scorch
Although less influential, the following factors can also contribute:
- Recent planting
- Soil compaction
- Poor drainage
- Nutrient deficiencies
- High salt concentration in soil
- Wilt diseases
How to Prevent Leaf Scorch
Leaf scorch does not typically kill healthy plants, but prevention and proper care can significantly reduce its impact:
- Use supplemental irrigation during prolonged dry periods. Water trees every 10–14 days, and water newly planted trees and shrubs every 7–10 days.
- Maintain consistent soil moisture by mulching with organic materials such as wood chips, and ensure water penetrates deeply into the soil.
- Apply fertilizers in early spring or late fall after leaf drop to avoid root burn. Avoid fertilizing in summer when soil is dry.
- Continue pruning dead, diseased, or crossing branches to improve plant health.
