From watching a local garden show last night, I understand that the roots
must physically touch for there to be a problem.

"Ben Sharvy" wrote in message
om...
Just lop it off a couple of times.

Contrary to popular myth, juglone doesn't instantly kill everything it
touches. the effect from a one year tree will be trivial.

There's more information about both asparagus and black walnut at:
http://www.efn.org/~bsharvy/edible.html