TIL a 70 foot oak in Portland was saved by a new root collar spray

I always thought root collar excavation was just for looks. Then I read a case study from Oregon State where they used a phosphite spray after clearing girdling roots. The tree put on 3 inches of new growth the next season. Anyone used this method on mature hardwoods?

3 comments

3 Comments

victor_carr251mo ago

Wow, that's amazing! I saw a similar study about phosphite helping stressed trees fight off root rot.

terrywilson23d ago

Yeah, that phosphite stuff is a real game changer.

rosel501mo ago

That reminds me of a sugar maple in our old neighborhood. It had a terrible lean and the roots were strangling it. The city arborist did a root collar excavation and used a mycorrhizal fungi treatment instead of a spray. The tree straightened up almost completely within two years.