Fertilizing Landscape Trees and Shrubs Part 2

Determining the Need to Fertilize

Visual inspection of trees and shrubs is often the best overall factor to use in making fertilization decisions.
Look for:
Poor leaf color (pale green to yellow)
Reduced leaf size and retention
Premature fall coloration and leaf drop

Soil Test

18 nutrients are required by plants: carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur and 9 trace minerals: iron, boron, copper, manganese, molybdenum, zinc, cobalt , nickel and chlorine. Carbon, oxygen and hydrogen operate in the formation of plant cells and food fabrication, the first two furnished from the atmosphere and the latter received from water soaked up by roots.

A soil test furnishes specialised data on the potential for plant reaction to agricultural limestone and to phosphorus and potassium fertilizers. In addition it provides a verifiable basis for ascertaining how much of those elements to add once they are found to be lacking. A representative soil sampling can be a challenge to get, because most nutrient-absorbing roots of trees and bushes are in the upper six inches of the soil and may stretch out two or three times beyond the radius of the crown. Consequently, in determining the nutritional demands of trees and shrubs, it's also essential to look at soil and moisture conditions; the species, age and vigor of the plants; and previous fertilization.

Nitrogen, the most typically depleted soil nutrient, furnishes the greatest growth response. Unfortunately, soil tests or analyses for accessible nitrogen are not very dependable. Nitrogen is present in different forms (e.g. nitrate, ammonium, urea) and these forms can alter rapidly in the soil. All the same, overall tree growth, especially root and shoot elongation, leaf color and leaf size, can be heightened with increases of nitrogen. Be sure not to overfertilize with nitrogen. Don't overcompensate with greater amounts of nitrogen when fertilizing grass, bushes and trees. Nitrate leaches readily from numerous soils and can create water pollution problems.

Selecting a Fertilizer

A variety of fertilizer types exist:
 Complete (N-P-K) vs.. incomplete (one or more select nutrients)
 Organic vs. inorganic
 Fast release vs. slow release
Dry (granulated, pelletized, spikes, pulverized encapsulated) vs. liquid

To assist in determining the form of fertilizer to utilize, weigh these factors: type of flora, season, wanted rate of plant reaction, application program and equipment price, proximity to water sources, consequence of soil type and pH, type of deficiency, and outcomes of a soil test or additional sampling methods.

Nearly all landscape plants profit from a slow secreting nitrogen fertilizer that can be organic or inorganic. Remember that nitrogen is easily washed through the soil, but phosphorus and potassium are not, signifying they necessitate less frequent application.