Found out Norway maple roots can actually poison the soil around them

I was reading through an old issue of Arborist News my boss had lying around, and there was this whole section on allelopathy. Apparently Norway maples release chemicals through their roots that kill off grass and other plants trying to grow near them. I always just blamed the shade for why nothing grew under them, but it's actually the tree actively fighting for space. Has anyone else noticed this making it harder to plant under big Norway maples on their jobs?

2 comments

2 Comments

thompson.nathan1mo ago

Read a study once that said Norway maple leaf litter breaks down differently too. The compounds in the leaves actually slow down decomposition, so the soil underneath gets this thick mat that other seeds can't get through. Combined with the root chemicals, it's like a double whammy. Tried planting shade tolerant hostas under one at my old place and they just shriveled up. The soil had this weird dusty smell to it, not like normal forest soil at all.

parkera221mo ago

Wonder if that chemical warfare is messing with the mycorrhizal networks in the soil too, since fungi are usually the first thing to die off when allelopathic stuff builds up. Could be why even the tough native trees struggle to get established nearby, right?