The lone voice of horticultural reason

“The soil under and around pine trees and oaks is acidic”

 I’ve heard that for years, probably heard it before I started gardening and it isn’t true. Or rather, sometimes the soil in these areas is acidic, sometimes the soil is neutral, and sometimes the soil is alkaline.

A far greater factor to soil pH than what’s growing on top of it is what type of rock is below. Years of pine needle and oak leaf drop will lower soil pH to a mild degree, but if you’re gardening near the limestone bluffs of the Mississippi you can have centuries-old areas of oaks or pines where the soil will test 7.8 (high alkaline).

Nine times out of ten, the hosta, lamium, or ajuga you planted around the skirt of a pine, or underneath an oak, didn’t die because the soil was too acidic. The plants died because they didn’t receive A LOT of watering in their first two years to help establish a deep, healthy root system. If you relied on scant watering, or rainfall, the tree sucked it all up, and the plants underneath petered out due to dry soil, not deathly acidic soil.

Don’t automatically add lime to soil under and around oaks and pines. More often than not, you’ll be raising the soil pH from slightly acidic—which is perfect for ninety-five percent of what we grow in the north—to a fairly stout alkaline, which few plants prefer. If in doubt, get a soil test.

Don Engebretson
The Renegade Gardener