MYTH: The best way to plant trees and shrubs is to add soil amendments to newly-dug hole

MYTH BUSTERS SERIES

THE FACTS

Adding organic matter, fertilizer or other substances to the planting hole of a LARGE TREE or PERENNIAL SHRUB can REDUCE plant growth

Adding amendments to backfill promotes root growth, but

- Roots and water DO NOT move well across the interface between amended soil and native soil 

• when roots hit the edge of the hole and encounter natural soil, they can circle back into the amended soil and create a ROOT-BOUND plant

- If organic amendment is not completely decomposed it may cause large trees and shrubs to settle

• The root collar may sink below the soil and predispose the plant to a host of health problems.

USE ORGANIC AMENDMENTS AS A TOP DRESS AROUND TREES AND SHRUBS

Sources:
Oregon State University Extension
https://www.oregonlive.com/hg/2017/02/gardening_myths_debunked_by_or.html

Washington State University Extension
https://s3.wp.wsu.edu/uploads/sites/403/2015/03/soil-amendments.pdf

https://s3.wp.wsu.edu/uploads/sites/2076/2015/05/C100-Planting-Trees-Shrubs-15.pdf

Root Washing
https://www.finegardening.com/article/root-washing-why-and-how-to-wash-roots