Amending Soil – Does It Work

Q: I was told by a landscaper that it was not necessary to add anything to the hole when planting new shrubs. I live at pinetree country club and nothing but clay do I see. What do you recommend.

A: Your landscaper is partially right. Research does not show much growth improvement in trees or large shrubs when the soil is amended. The reasoning is that the roots of these large plants should be encouraged to quickly outgrow the planting area. Adding amendments makes the roots want to stay close to the plant and this can lead to drought damage. A wide area, perhaps ten feet in diameter, should be thoroughly loosened before planting trees or large shrubs. On the other hand, small shrubs and perennials do not have extensive root systems. For them, It makes sense to add organic matter and mix it with existing soil before planting.