Tree and Shrub Fertilization

“Fertilization is the most cost-efficient maintenance you can do for your trees.  Your trees and shrubs should be on an annual program of slow release fertilization.  A healthy tree, able to cope with city life, adds value to your property and to your quality of life.”

Tree fertilizerAll trees need essential minerals and nutrients to grow and remain vigorous.  In the forest, these nutrients are provided by decomposing leaves and wood.  In our yards we routinely remove this debris, robbing our trees of the essential products they require to produce food. Many tree owners are under the false impression than lawn fertilization will provide their trees adequate nutrition.  Our grass lawns are very efficient competitors and little fertilizer gets past the grass to the trees.  Fertilizing grass and adding and adding a little extra for the trees does not work well.

The root system of an open grown tree spreads out about two to three times the height of the tree, much further than most people would imagine.  Around our homes, we restrict this root spread with barriers such as streets, foundations, underground utilities, and sidewalks.  Essentially, our trees are like potted plants and we need to provide fertilizer much as we would for a house plant. Fortunately, our native trees are able to endure some very challenging conditions.  Some conditions are natural; like the drought we frequently experience.  Others we cause; such as topping, cutting roots, compaction, and chemical burn.  Providing supplemental nutrients to confined root zones helps trees develop better root systems to better cope with these adverse impacts.

Deep root fertilization is the best method for installing fertilizer into the root zone of a tree.  The aeration that occurs in the process helps counter compaction and adds oxygen to the soil.  The water that carries fertilizer into the soil is very beneficial during drought conditions.

We recommend fertilization of your trees and shrubs on an annual programmed plan with a complete organic fertilizer.  In Texas, our recommendation is BioPak PlusBioPak Plus is a blend of beneficial rhizosphere bacteria and water- soluble chelated micronutrients, organic amendments, and yucca plant extract.  Nitrogen fixing bacteria use atmospheric nitrogen that eventually biodegrades into forms used by your tree.  Phosphate-solubilizing bacteria convert the phosphate abundantly available in our soils into soluble forms.

An organic nutrient complex enriches the soil profile immediately surrounding roots, increasing organic content of the soil, and improving nutrient availability.  The micronutrient package has chelated iron, manganese, magnesium, boron, and zinc; all formulated in water soluble forms.  Yucca extract is also present to help with compaction and sulfur to help lower pH.  Sea kelp adds a little nitrogen, and humic acids improve nutrient uptake.

BioPak has a system of microbial activity that through decomposition of natural and introduced organic matter makes essential mineral elements soluble so that they are available to plants for metabolic requirements and normal growth.  BioPak enriches the organic content of the soil profile and helps restore the bioactivity to sterile or depleted soils.  Its microbial activity encourages soil aggregation that over time improves soil porosity, water movement, drainage, and aeration.  This soil fertility program will not burn or harm roots.

In severe cases, complete organic fertilizers can by supplemented to help correct critical problems such a compaction after construction or iron chlorosis.  We sometimes add Mycor to help restore beneficial mycorrhizal fungi to compacted soils after construction.  In central Texas we often add additional chelated iron (138-Fe) to help with iron chlorosis and may even recommend foliar spray in severe cases.  In cases of zinc deficiency, we only recommend foliar sprays because our soils tie up zinc faster than plants can pick it up even when it is chelated.  Most blends of complete fertilizers are not adequate to overcome extreme problems and require some sort of supplement aimed at the specific problem.

Fertilization is the most cost-efficient maintenance you can do for your trees.  Your trees and shrubs should be on an annual program of slow release fertilization.  A healthy tree, able to cope with city life, adds value to your property and to your quality of life.

David Vaughan,
Certified Arborist
Etter Tree Care