Micro-injection constitutes the direct injection of necessary nutrients into the trunk of the tree or bush. It's an acceptable commercial use for remedying or invigorating trees demonstrating stress or decline symptoms. Nutrients can as well be solidified into gelatin capsules and imbedded in holes in the trunk. Micro-injection research is comparatively limited and outcomes are often conflicting. Boring holes, imbedding or injecting fertilizer and sealing holes could lead to trunk disfigurement and decay. Foliar applications, injections or implants would better be used only when soil application of fertilizer is unrealistic. These routines are regarded as short-term remedies for nutrient deficiencies and pest infestations. In the final analysis, suitable soil and foliar applications must be applied for a permanent cure.

Fertilizer Placement
Fertilizer should not be concentrated around the base or trunk of a tree or shrub, but should be applied over as much of the plant's root zone as possible. For trees and shrubs, fertilizer should be applied over an area twice as large as the crown spread. Since most landscape plant roots grow in the top foot of soil, surface, but not deep application, is recommended.

Factors Affecting Fertilizer Uptake
Numerous elements impact how easily and well trees and bushes assimilate fertilizers. The most significant uptake factors are:
1.Fertilizer variant (inorganic, quick release, or fluid forms are assimilated faster than organic, slow-release, or dry forms)
2.Soil type (clay particles and organic matter assimilate or bind more nutrients than sand, so fertilizer needs to be applied more frequently in sandy soils, but with lesser rates each time due to leaching potential)
3.Soil moisture content and soil temperature (nutrient uptake is faster in moist warm soils)
4.Plant vigor (plants under stress are more ineffective in assimilating available nutrients because of damaged or decreased root systems)

Application Timing
Fertilizer should be given when plants require it, when it will be most effective, and when plants can readily take it up. Late summer and early fall fertilization may rouse new growth that is not winter hardy, and summer drought may interfere with nutrient uptake, but spring, fall, and winter applications are acceptable. A split application may be beneficial, applying half the yearly rate in early spring and the rest in the fall as or after plants go dormant.

If water is unavailable, do not fertilize at all - plants will be unable to take up the nutrients. (During a dry season, fertigation - application of fertilizer through an irrigation system can be valuable.)

Tree and bush fertilization comprises only one part of aggregate plant maintenance. Fertilization might not benefit a plant if it's under stress from inadequate soil aeration or drainage, sodden soil, deficient light or space, or excessive pest problems. Altogether factors determining plant growth should be kept at optimal levels to guarantee plant vigor.

Related posts:

1. Fertilizing Landscape Trees and Shrubs Part 3
2. Fertilizing Landscape Trees and Shrubs part 1
3. Fertilizing Landscape Trees and Shrubs Part 2