If you care about the health of your trees, you’ll want to not only address the pest and disease problems, but also the nutritional needs. When it comes to fertilizing trees, there is a lot of misinformation out there. These myths about tree fertilization come from a variety of sources and for a variety of reasons. This list is just a few we commonly hear.
Myths about Fertilizing Trees
1. Trees grow fine on their own. They don’t need fertilizer. FALSE. When trees grow in environments that aren’t their original habitat or are adapted to urban or suburban locations, they often utilize what is already there, creating deficiencies. Fertilizer is meant to replace what is missing or used up. Remember the natural habitat of most trees. They’re in a forest. They have cool, moist soil from the shade of other trees and don’t get impacted by drought as much as our landscape specimens. The leaf litter is constantly recycling composted nutrients back into the soil. They don’t have lawn areas to compete with. They aren’t mixed in with non-native plants that bring in foreign pests and diseases. Even in nature, trees don’t grow fine on their own without challenges. They’ll need more help when we put them in a landscape.
2. Fertilizing a tree will always improve a plant’s color. FALSE. There are many factors that influence a plant’s color. Poor color could be a problem impacted by the pH of the soil, disease, insect damage, planting depth, excessive moisture, inadequate moisture, not enough sunlight, and more.
3. Fertilizing a tree is like a shot of vitamins or steroids. FALSE. Fertilizers are not a wonder tonic or magical serum. They replace natural elements found in soil. If a soil is rich in all of the nutrients a tree needs and it is the proper pH and the exposure to light and availability of moisture is correct, that will also help a tree. Fertilizer is no substitute for addressing pest and disease issues. In fact, some pest and disease problems can be aggravated with excessive fertilization.
4. All trees need “deep-root” fertilization. FALSE. If a tree is young, and is in a mulch bed, you can deliver fertilizer in other forms than liquid, such as a granular material. However, when trees get larger and spread out into turf areas, you’ll want to consider liquid injection approximately every 18″ throughout the area under the canopy. The advantage of using a liquid-injected tree fertilizer method is delivering this material below the grass roots. A tree’s root system is predominantly found in the top 8″ of soil. Below this depth there is very little root development as the soil contains little oxygen which roots need.
5. Organic fertilizer is better for trees than synthetic fertilizer. FALSE. A plant only uses nitrogen in the nitrate form. Organic fertilizers need microorganisms in the soil to break down the nitrogen to become nitrate. Synthetic fertilizers can provide the nitrate form immediately. If your soil has the necessary microorganisms in it, it will convert over a slower period of time, but there isn’t any advantage of one over the other.
6. Fertilizing will make your trees grow faster. FALSE. The truth is that soil can only hold on to a certain amount of nutrients at one time. Once the soil is saturated with nutrients, the surplus nutrients can’t be used by a tree until a later time. There are many factors that influence growth rates of plants, and proper tree pruning can also promote better growth and a fuller canopy.
Trees often benefit from annual fertilization set up on a Plant Health Care Program. This will help replace the typical elements trees use in a given year. You should also periodically perform a soil test for your trees to make sure all of the nutrient deficiencies and soil pH are at levels that will help your tree to perform at its best. If deficiencies exist, a professional tree service with Certified Arborists can help configure the recommended treatments to get your tree what it needs. Fertilization is just one aspect of a Plant Health Care program that need addressed. Finding a knowledgeable pro can make a big difference.
If you have concerns about your trees and how they can be healthier, we’d be happy to talk further with you and offer you a free consultation for your trees and other plants in your landscape.
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