Fertilize Shrubs: Why It Is Important

Fertilizers provide essential nutrients to plants that support their growth. They keep plants healthy and prevent malnourishment. Also, they protect plants from fungus and harmful insects. But when fertilizing plants in your yard, don’t forget  to fertilize shrubs too.

It’s because shrubs need nutrients – sometimes. So, choose the right fertilizer and apply it at the appropriate schedule.


What Is Fertilizer?

Many people tend to misunderstand and misuse fertilizer. Fertilizer isn’t “food.” Rather, plants produce their own food in the form of sugars through photosynthesis. So, fertilizers provide minerals or nutrients that help in photosynthesis and growth.

When fertilizing trees and shrubs, keep these two points in mind:

  1. Fertilizer is beneficial when plants need it
  2. Use it in the right amount, at the right time, in the right place


Establish the Need to Fertilize Shrubs

Are you unsure whether or not you should fertilize shrubs and trees? Then inspect the following factors to make the right decision:

Soil Test

Testing yard soil is crucial. A soil test determines the acidity or alkalinity (pH) of soil. Also, it highlights the level of nutrients the soil contains. The results help you decide if you should add nutrients to make up for deficiencies in the soil.


Look at shrubs and trees for signs of poor growth such as:

  • Poorly colored leaves (pale green or yellow)
  • Leaf size may be smaller than normal
  • Leaves may develop fall colors before the season arrival
  • Leaves falling off the plants
  • Little annual twig growth
  • Twig or branch dieback

These symptoms of poor growth aren’t always related to low levels of nutrients in the soil. Insects, weeds, diseases, heavily compacted soil, or adverse weather conditions may also cause these issues.

You shouldn’t assume that fertilizers would cure these problems. It’s important to determine the cause of the problem and correct it before fertilizing.

Planting Age

Fertilizer works best when you apply it in the early years. Slow-release fertilizers are best for young plants, trees, and shrubs. You can also apply it to older, transplanted trees. This way, it speeds up growth and helps young trees fill their allotted space in the landscape.


Kind of Fertilizers to Fertilize Shrubs

Two kinds of fertilizers are available to fertilize shrubs: fast-release and slow-release.

Fast-Release Fertilizers

Fast-release fertilizers are also called water-soluble fertilizers. These are cheaper than slow-release products. As a result, it releases nitrogen over an extended period. Its nitrogen is water-soluble and readily available to plants. But nutrients in a fast-release fertilizer may leach quickly through the soil.

In sandy, well-drained soils, the soluble fertilizer may move past the root system after only a few inches of rainfall or irrigation. In fine-textured clay soils, leaching will be slower. But its runoff may be greater.

Slow-Release Fertilizers

Slow-release fertilizers are also known as controlled-release fertilizers. They have longer release periods than their counterparts. These are suitable for young shrubs and trees. Slow-release fertilizers are also good for areas where the potential for runoff is high such as slopes or compacted soil. It releases nutrients slowly. So, it reduces the risk of fertilizer damage, burning, and water contamination.


When to Fertilize Shrubs

Fertilizers make up for inadequate minerals in the soil. You shouldn’t apply these to unhealthy shrubs that are carelessly planted or improperly watered. It’s because fertilizers can’t cure ailing plants or shrubs.

Apply fertilizers only when shrubs need them. Hence, they’d readily absorb the nutrients with their roots. Time your application to coincide with active root growth and adequate soil moisture. Early spring is the perfect time to fertilize trees and shrubs. You can apply light fertilizer in early summer if conditions are conducive to plant growth. In other words, this means optimal temperatures and enough soil moisture.

Avoid fertilizing drought-affected trees and shrubs during the summer months. Also, don’t add fertilizers if water is unavailable since plants won’t be able to absorb nutrients.

When it comes to fertilizing trees, apply the fertilizer to the root zone area. It’s a circular area with the tree in the center. The root zone area extends beyond the drip line or outermost branches of the tree. The roots may extend 1½ times the distance from the trunk to the drip line or outermost branches.