In a recording of the "Goon Show" from the late 1950s, Bernard Miles sings,

Wur be yon blackbird to?
I know wur 'e be.
'E sees I and I sees 'e,
And 'e knows I be a'er 'e.
Wur be yon blackbird to?
Up yon wurzel tree!

The tune is very close to that of "Where Did You Get That Hat", a Vaudeville song from 1888.

As somebody has mentioned, "wurzel" usually refers to the mangel-wurzel, which is a large root vegetable, not a tree (or bush). A blackbird, however, is sometimes called an ousel (pronounced "oozel"), and in some dialects, I think, a wousel (or, if you prefer, woozle, pronounced the same way). "Wousel" could easily have become "wurzel". It seems slightly less improbable that a tree with an ousel in it might be called a "wousel tree" than that a mangel-wurzel might be mistaken for a tree.