What is this growing on my hedge?

[PickledMuffin]

I have no idea what it is! I used Google lens’s but it came up with various nasties.

It’s slightly larger than a walnut.

Thanks!

Not sure at all. It does look like a nasty, a tumor or fungus or some sort of bug nest. I would be inclined to prune that branch off and put it straight into the household waste wheelie bin.

(Though the Sporner in me would want to disect it, first!)

I would say it is some sort of gall. Often has an insect inside. Leave it to grow.

Could be crown gall possibly.

I think it's a gall too. Likely harmless, don't pull it off, insects need all the help they can get.

Agree it's a gall. It's a good year for them, my little oaks are covered in them. According to the iNaturalist app it's a bacterial crown gall. Despite the name you don't necessarily need to remove it - advice under point 4 here: https://www.rhs.org.uk/disease/crown-gall

Lots of different gall wasp species make their own special orb/disc-ish object on specific plants species, it's quite interesting. I like the oak knopper gall.

Thanks for the responses, it is appreciated.

It looks like it should be called a brain gall!