I’m always amazed when I hear from customers that they have been told by other “nursery professionals” that newly planted trees and shrubs should not be fertilized. This would be true if you want your new plantings to grow and establish slowly, display poor color, flower weakly and remain for a longer time in a stressed out condition that invites attack by garden pests.
If on the other hand you want your newly planted trees, shrubs, perennials and annuals to establish quickly, have great color, flower wonderfully, and quickly recover from planting / transplanting stress, then making moderate amounts of plant nutrients available to the plants on a consistent, even, and everyday basis will give you the vibrant plants you want. I want to emphasize the importance of moderation and consistency in the availability of both nutrients and water. Too much of either will certainly cause trouble.
The nutrients plants need in moderation can come from many sources. High quality topsoil that is 12” to 36” deep, loose, crumbly and un-compacted, and high in organic matter content and properly drained is the very best place to start. Even soils this good can benefit from the addition of a modest amount of fertilizer, especially during the first 3-5 years when a new landscape plant is expanding the size of its root system.
I think the reason that some people recommend no fertilizer for landscape plants is that they have seen fertilizer misused, applied excessively and carelessly and seen the excessive levels of fertilizer burn roots and stunt plants or even kill them. I have seen this happen. It’s certainly unfortunate, but in no way means that we should never help plants have the nutrients that will help them perform at their full potential.
Compost and manure are organic fertilizers that work really well for trees, shrubs and perennials. Simply work compost and manure into the soil prior to planting and continue to add surface applied compost and manure in moderate amounts for several more years. In the long run, organic mulches like shredded bark and chips that are applied / re-applied about every two years will also provide a slow releasing source of plant nutrients.
Other types of fertilizers such as fish emulsion, processed manure, Miracle Grow, Miracid, 10-10-10 and slow-release Osmocote can all be excellent sources of nutrition for landscape plants, as long as they are used in moderation. The problems arise when fertilizers are applied too heavily, and either plant roots are damaged, or some fertilizer is not able to be utilized by the plant and leaches into lakes, streams and aquifers.
To help assure that virtually all fertilizer applied is used up by the plants I like to apply timed release fertilizers to new plantings in the landscape as well as the plants in our field and container production. Nutrients are slowly and continuously made available over a period of 3-6 months during the growing season and release of nutrients pretty much stops when soils cool and finally freeze with the onset of winter.
High quality compost and Osmocote time release fertilizer beads are my two favorites for the best long term results. When plant materials need a quick jump start, an application of water soluable Miracle Grow or Miracid fertilizer provides a wonderful boost and is a very diluted solution that gets used almost entirely.
When trees and shrubs become more established the need for fertilizer diminishes because they have very large root systems that can draw small amounts of nutrients from very large volumes of soil. Most of the needs of established plants can be satisfied by the application of organic mulches and compost to the soil surface, with a small amount of timed release fertilizer on occasion.
Your trees, shrubs, perennials and annuals are living organisms. They need nutrients and water in amounts that are moderate and consistent just like puppies and new born babies need us to provide for their needs. Don’t forget to provide you new plantings with just enough and never too much water, sunlight and nutrients. They will reward you with years of beauty and enjoyment.