It’s not just your grass that could use a boost this time of year. You often need to consider a fall fertilizer for trees and shrubs, too.
Most soils in Michigan can typically provide an adequate nutrient reserve to meet the needs of trees and shrubs. Even those that are planted next to lawns can get some of their nutrients from lawn fertilizers. That being said, depending on the properties of your soil, nutrient deficiencies can occur.
So, let’s take a look at why you should consider fertilizing your trees in the fall and what the best fall fertilizer is for them.
When To Apply A Fall Fertilizer For Trees
It used to be that trees and shrubs that needed a nutrient boost got their annual fertilizer application in early spring. It’s the time just before active growth begins for the year. Many experts accepted this timing for years. And although early spring is a good time, new research indicates there is an even better time.
Now a majority of arborists consider late September or October a great time to consider a fall fertilizer for trees and shrubs. They say to apply it then, or about a month after the first killing frost. Why? Because plants (including trees) will use the nutrients they need in different ways throughout the year.
Most Common Nutrient Deficiencies In Trees
Here are the three most common nutrient problems that homeowners in Michigan typically see in trees and shrubs. They are deficiencies of nitrogen, iron, or manganese.
Nitrogen deficiencies may occur in trees since it is the element that is needed in the largest amounts. The reasons that trees become deficient in nitrogen include:
- Most of them are located in mulch beds that use up nitrogen as they decompose.
- It is lost from the soil over time through leaching.
- Removing leaves each fall interrupts the natural recycling of nitrogen that occurs in native forests.
Think about that last one the next time you’re raking leaves.
Iron and manganese deficiencies are common in certain landscape trees. These deficiencies are typically associated with alkaline soil pH. In both cases, soils may contain adequate amounts of the element, but availability and uptake are reduced by alkaline soil conditions.
The Best Fall Fertilizer For Trees
Most experts recommend applying 1 to 3 pounds of slow-release nitrogen per 1,000 square feet of tree bed and cultivating lightly. But to figure out the exact amount of fertilizer you’ll need, you’ll have to do some math.
Start by calculating the square footage of your beds. Then take those measurements with you to your local garden center and determine how much you’ll need. 
Using a slow-release fertilizer is important. That’s because there will still be nutrients in the soil come spring when your plants start to grow. A slow-release fertilizer also ensures that your trees get the right amount of nitrogen and not too much at one time.
If you have a tree or shrub that does not flower well, a dose of superphosphate will help promote flower growth. However, if the plant is not located in the right spot, all the superphosphate in the world won’t make it flower.
When Not To Fertilize A Tree
And keep this in mind. Don’t fertilize newly planted or newly transplanted trees. These are trees that were planted or transplanted less than two years prior.
Applying fertilizer to newly transplanted trees can excessively dry roots. This is called burning. Wait until after the third year before you consider fertilizing it. At that point, it will be considered an established tree.
Let Safari Tree Help
Safari Tree’s year-round applications include a fall deep-root-feeding that delivers nutrients straight to the root system of your trees. This helps your plants recover from the long hot summer and prepares them for the cold winter season ahead.
You’ll also get a fall anti-desiccant spray. It winterizes your evergreen trees and shrubs.
If you’re going to need help winterizing your yard, contact us today. We’ll be happy to help.
