Fertilizing Trees: Best Practices for Strong Roots & Healthy Trees

Maintaining healthy trees in your landscape not only enhances the aesthetic appeal but also increases the value of your property.

As trees provide shade, beauty, and increased property value, keeping them in top condition is essential. Trees, like all living plants, require adequate nutrients to thrive.

Applying the correct tree fertilizer can help stimulate growth, improve resistance to diseases, and ensure healthy trees that enhance your landscape for years to come.

Understanding Tree Fertilizer: What’s in It?

The fertilizer you use for your trees is often composed of three main nutrients: nitrogen, phosphorus, and potassium (often listed as N-P-K on the package).

These are known as the three numbers on a fertilizer bag and indicate the relative amounts of each nutrient:

• Nitrogen: promotes new growth and helps develop lush foliage.
• Phosphorus: aids in root development and flowering.
• Potassium: sometimes referred to as potash, improves the overall hardness of the tree and helps it withstand environmental stresses.
• Other nutrients: trees sometimes require additional micronutrients like calcium, magnesium, or iron. Iron chlorosis, a condition caused by iron deficiency, results in yellow leaves and poor growth. Trees in alkaline soils are particularly susceptible to iron chlorosis.

When to Fertilize Trees

For best results, fertilizing should be done during early spring, late summer, or early fall. These periods allow trees to absorb the nutrients more effectively and prepare for seasonal changes.

Newly planted trees benefit from an initial dose of fertilizer to establish strong roots, while established trees may only need to be fertilized once every few years.

How to Determine Your Tree’s Nutrient Needs

Before applying fertilizers, it’s crucial to determine the specific nutrient requirements of your trees.

Start by analyzing the soil through a soil test. Conducting a soil test report will reveal the levels of nitrogen, phosphorus, potassium, and other vital nutrients in your soil.

It also indicates the soil pH, which affects the availability of nutrients to the roots.

If having your soil tested reveals some nutrient deficiency symptoms, such as stunted growth or yellowing leaves, you may need to adjust your fertilizer application.

For example, iron chlorosis is common in alkaline soils and can be addressed by applying fertilizers containing iron.

Types of Tree Fertilizers: Granular vs. Liquid

There are different types of fertilizers available:

• Granular fertilizers: These are slow-release and can be spread around the drip line of the tree, ensuring a steady supply of nutrients.
• Liquid fertilizers: These are quickly absorbed by the roots and are great for newly planted trees or trees showing severe nutrient deficiencies. A liquid fertilizer can be applied directly to the soil surface or mixed with water for foliar feeding.

Each type has its benefits, and the choice depends on the tree’s specific needs and your soil types.

Liquid fertilizers are especially effective if you need immediate results, while granular types provide sustained feeding.

How to Apply Tree Fertilizer

Properly applying tree fertilizer is key to promoting healthy trees. Here are some general guidelines:

Identify the Drip Line

The drip line is the outer edge of the branches where water naturally drips to the ground. This is where most of the roots spread and where you should apply fertilizer.

Determine the Right Amount

Use the recommended fertilizer dosage based on the tree’s size and soil test results.

As an example, for a mature tree, you may need to apply an amount of 1 to 2 pounds of fertilizer per trunk diameter’s inch. Be careful not to exceed the recommended amount, as excessive use can burn the roots.

Spread the Fertilizer Evenly

Apply the fertilizer around the drip line, not directly against the trunk. Rake it lightly into the ground and water it thoroughly to help the fertilizer reach the roots.

Use Mulch

Adding a layer of mulch after fertilizing can help retain moisture and protect the tree roots from extreme temperatures.

Special Considerations for Different Soil Types

Different soil types affect nutrient absorption. For instance:

• Sandy soils quickly drain and may require more frequent fertilization to ensure nutrients remain available.
• Clay soils retain water but can become compacted, making it harder for nutrients to reach the roots spread.

It’s essential to have your soil tested to understand its composition and adjust your fertilizer regimen accordingly.

Recognizing Nutrient Deficiency Symptoms

Nutrient deficiency symptoms in trees can manifest as:

• Yellowing leaves (common with iron chlorosis)
• Poor new growth
• Sparse or stunted foliage

If you notice these issues, a soil test can help determine if your trees lack specific nutrients like nitrogen, phosphorus, or potassium.

Caring for Established Trees and Shrubs

Established trees and shrubs may not need regular fertilizing if they are already thriving.

However, if the soil test report indicates low levels of available nutrients, periodic fertilization can stimulate healthier growth.

The key is to fertilize in moderation and avoid excessive application that could damage your landscape.

Special Fertilization Tips for Conifers

Conifers, such as pines and spruces, have specific nutrient needs. It’s best to fertilize them in early summer or early fall with a fertilizer high in potassium to promote hardiness.

Be cautious with nitrogen, as too much can lead to rapid, weak growth.

The Role of Irrigation

Proper irrigation is crucial after fertilizing. Whether using granular or liquid fertilizer, thoroughly irrigate the soil to help dissolve the nutrients and deliver them to the roots.

If there’s insufficient rainfall, supplement with watering to ensure fertilizer absorption.

Choose the Best Lawn Care Company in the Midwest, Choose SunCo

In the Midwest, where the weather and soil types can vary greatly, it’s important to use the right fertilizer to keep your landscape vibrant.

By taking the time to determine your tree’s needs through a soil test, selecting the appropriate fertilizer, and applying it correctly, you can ensure healthy trees that continue to enhance your property.

At our lawn care company, we specialize in fertilizing trees, shrubs, and lawns to help maintain the health and beauty of your landscape.

Whether it’s diagnosing nutrient deficiencies, conducting a soil test, or applying the recommended fertilizer, we are here to help you achieve the best results.

Contact us today to learn more about our assortment of lawn care services! Call us at (402) 972-8603 or visit our website to schedule a consultation with our lawn care experts.