Why Are the Leaves on My Shrub Turning Yellow?
Yellowing leaves on your shrub are usually a cause for concern, but the problem may have you scratching your head in wonder. Unfortunately, there are many reasons the leaves may yellow, and it isn’t always easy to determine the exact cause.
The following are some of the most common reasons for yellow leaves on your shrubs.
Is It Nutrient Deficiency?
All plants need specific nutrients for growth and produce the energy they need to drive metabolic processes. These essential nutrients all have different roles in the plant and are required in varying amounts. Because some nutrients like nitrogen are critical for producing chlorophyll, a nutrient deficiency results in the leaves turning yellow.
If you are experiencing a nutrient deficiency, it’s best to apply a quick-release, water-soluble fertilizer to your shrub through soil or foliar application. Always use per the label recommendations and choose a micronutrient formulation if possible.
Is It Fertilizer Damage?
While fertilizer is often necessary for plant growth, you must be careful when using synthetic formulations. These products are made with chemicals salts that can cause problems when too much fertilizer is applied. As these salts build up in the soil, they “burn” the roots and make it hard for plants to take in water. The salts can also be toxic at high levels in plants.
To prevent fertilizer burn, always follow label recommendations when applying fertilizers regarding the correct application rate. Periodically flush the soil with water to leach the salts out of the root zone.
Is It Drought Stress?
One of the most common abiotic stressors in shrubs is inadequate soil moisture. When there isn’t enough moisture in the soil, plants can’t take in water and nutrients through their roots leading to a nutrient deficiency.
To prevent and treat drought stress, keep the soil around the base of your shrubs consistently moist, without overwatering to the point the ground is soggy, and there is standing water.
Is It Salt Damage?
Beyond fertilizer damage, shrubs often experience salt damage when grown close to sidewalks, driveways, and roadways in areas with heavy winter snowfall. These surfaces are usually covered with ice melt or salt for safety during the winter. As they make their way into the soil, they can cause toxicity in the plant, and the leaves may be yellow.
Flush the soil with clean water as the weather warms and spring arrives to correct salt damage from deicers.
Is It Winter Burn?
Winter burn is a common problem in many evergreen shrubs, brought on by dry conditions and a lack of moisture. More specifically, it is caused by desiccation brought on by freezing temperatures and cold winter winds stripping water from the shrubs’ leaves, causing them to discolor and die.
Unfortunately, there is no way to treat or repair the damage once winter burn occurs, so prevention is critical.