How to Choose a Tree and Shrub Fertilizer
In the forest, soil nutrition comes from decaying organic matter on the ground, but in urban and suburban environments, soil composition and water drainage has been significantly disturbed, and gardens and yards are cleaned of organic debris. This is why tree and shrub owners might consider using fertilizers annually or as needed. Choosing a fertilizer wisely can help you maintain a healthy landscape in a timeframe, budget and method that best suits you.
When shopping for a fertilizer, there are 3 things to decide on:
1. Ratio of N-P-K. Each macronutrient (Nitrogen, Phosphorous and Potassium) promotes different plant reactions, which is the significance of the numbers. Fertilizers with higher rates of Nitrogen encourages abundant new leaf growth, high Phosphorous encourages root growth and Potassium encourages drought tolerance and winter hardiness. For these reasons, Fertilizers that are high in N are applied in the spring and high in K in the Fall.
2. Synthetic/Chemical or Organic. Organic Fertilizers have lower N-P-K amounts than Synthetic ones. Organic fertilizers are made from composted organic materials like fish, blood, manure, etc. and can increase soil activity and structure. Synthetic fertilizers are fast acting and are sometimes blended with pesticides or have other engineered properties such as slow release biodegradable capsules.
3. Granular or Liquid formulas. Granular may be a good choice if you already have a spreader handy, whereas some liquid products are available that you can attach onto your hose end for easy spray application.
*Always follow application rates on products to avoid pollution, plant injury and/or pest problems.