Trees require both macronutrients and micronutrients based on the quantity required for healthy growth. The macronutrients required by plants for growth include nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). Addition of macronutrients, especially nitrogen, can result in improved growth while deficiencies can lead to slower growth and visible symptoms. Micronutrients, which are required in very small amounts, include iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), chlorine (Cl), and molybdenum (Mo). Tree nutrition is a balancing act wherein too much or too little of a given nutrient can be detrimental.
The best indicator of whether fertilization is necessary is a soil test. Ideally, a soil sample should be taken before trees are planted. Additional samples can be taken every 3 to 5 years thereafter to determine whether any nutrients are lacking. Foliage color is another indicator of nutrient status. Yellow, off-color, or scorched leaves is an indicator of deficiency of one or more nutrients. Many fertilizers exist to supply trees in Colorado with required nutrients. Timing of application is also critical for effective nutrient take-up. Additionally, different fertilization regimes should be used during different phases of a tree life-cycle, from planting and new growth to healthy, mature trees. Let the professionals at Walker Tree Care help you assess the needs of your beloved trees and keep your property at its healthiest.