Tree identification

Sandysears

Our garden is surrounded by enormous tree and over the past couple of years we have had these small plants coming up all over the garden. We try to remove them but they have very deep and strong roots. Any ideas as to what they are?

Dovefromabove

I’ll link these two to avoid confusion

https://forum.gardenersworld.com/discussion/1029637/tree-identification#latest

ship5cat

Did you find out what they are?
i seem to have the same, would love to know.
many thanks