Tree fertilization is a crucial part of arboreal maintenance. It allows trees to grow fully and healthily, facilitating their appearance and longevity. It also serves to correct and prevent developmental problems that can stunt growth and lead to defects in leaf production, flowering, and fruit development. 

There are different types of fertilizers and fertilization methods available and each of them is suitable for specific situations and tree species. As such, the team at Croft Tree Experts would like you to know everything you need to about tree fertilization.


What is Tree Fertilization?

Tree fertilization is the act of providing trees with the required nutrients to facilitate their growth and development fully. If the trees are not getting enough nutrients from the environment around them, the nutrients are artificially introduced into the environment or directly applied to the tree itself. The fertilizer is applied as a granular compound, a liquid injection or an aerosol spray.


An important note is that when you fertilize a tree, you are not feeding it. Plants use photosynthesis to make their own food and the nutrients provide the necessary building blocks to make their food.


What Are The Benefits of Tree Fertilization?

Tree Fertilization granular

Tree fertilization provides numerous benefits when properly performed. They include;


  • Advancing healthy tree growth 
  • Fixing imbalances in the amounts of nutrients available
  • Compensating for the soil’s quality
  • Enhancing a tree’s aesthetic qualities
  • Increasing pest and disease resistance
  • Lengthening a tree’s longevity


How To Fertilize Trees

  1. Soil Application: When the fertilizer is in granular form, it can be applied around the tree’s base. The application can be done by hand or with the help of a mechanical spreader.
  2. Root Injection: With a specially designed injector, fertilizer can be introduced into the tree’s root zone. The type of fertilizer and the injector required make this method of fertilization very effective and expensive. As such, root injection is usually reserved for large trees or those that are severely nutrient deficient.
  3. Foliar Application: Fertilizer can also be applied to a tree’s leaves using a sprayer. The aerosol nature of the application makes this time-consuming and inefficient. However, the foliar application allows for the fertilization of trees whose roots are hard to reach and can correct specific nutrient deficiencies.

Tree Fertilization foliar

Ensure to follow all the necessary directions when performing tree fertilization. Using the correct amount for the tree’s species and size prevents overfertilization which can harm trees.


Types of Tree Fertilizer

There are four common types of compounds used to fertilize trees.

  1. Nitrogen fertilizers: Nitrogen is a vital nutrient for plant growth and is used in many fertilizers. It is available in numerous forms like granular, liquid and slow-release compounds.
  2. Phosphorus fertilizers: Phosphorus is also important for proper tree growth and development. It facilitates the growth of roots, flowers, and fruits in trees. Phosphorus is usually used in granular or liquid form for tree fertilization.
  3. Potassium fertilizers: To maintain their overall health and vigour over their lifespan, trees need phosphorus. Like nitrogen tree fertilizers, phosphorus fertilizers are also available in granular, liquid and slow-release forms.
  4. Micronutrient fertilizers: Trace amounts of other nutrients like copper, iron and zinc are also necessary for tree development. These micronutrients are often added to fertilizers intended for particular species or to correct specific nutrient deficiencies.


When You Should Fertilize Trees

Tree fertilization should always be performed in response to a particular need or as a solution to a problem. Hence you need to establish the need by investigating or watching out for symptoms.

  • Tree growth is an important and obvious sign that can let you know if you need to fertilize the trees. Leaf discoloration, below-average leaf sizes, shrivelled or dying branches, and other signs of malnutrition will indicate the need for tree fertilization. However, you need to also eliminate physical trauma, disease, parasites or environmental stress as a cause of the problem. These issues can also cause those symptoms so a careful analysis also needs to occur before making a decision.
  • Soil testing will determine the amounts of nutrients present in the soil, as well as the soil’s pH (the acid or alkaline levels in the soil). Soil pH is very influential on plant growth, when it falls out of the optimal range for a specific plant it can create nutrient deficiencies and other problems.
  • The location can also determine whether or not tree fertilization is needed. If the tree is growing in an area that is regularly fertilized, like a lawn, then there is no need. In urban areas or other environments where the required nutrients are in short supply, you may need to fertilize the tree regularly.
  • The tree’s age can also factor into the need for fertilization. When done properly, tree fertilization can accelerate the growth of young and recently transplanted trees. The use of slow-release fertilizers is also effective for foliage that has been planted recently.


Croft Tree Experts: Ottawa’s Tree Maintenance Services

Tree fertilization helps promote the growth and health of trees. Proper tree fertilization and maintenance ensure that trees have access to the necessary nutrients and prevent any deficiencies in growth and development.

Please contact us if you need any help with tree maintenance and fertilization. Croft Tree Experts has provided expert arborist services to Ottawa and the surrounding areas since 2015. Our team is highly skilled and dedicated to ensuring that your trees stay healthy and strong for as long as you need.