Yew vs Wistaria
 

When a wistaria spreads itself into a neighbouring yew tree, could this have
ill effects on the wistaria?
Odd question perhaps but I have two experiences of this.
My father planted a wistaria in 1953 and I grew up with it.
By 2003 it had a horizontal spread of about 40 metres around W/S/E of a
building.
Vertically it was about 18m as it had grown to the top of a large yew
closeby.
A remarkable sight when in full bloom
Unfortunately both my father and the wistaria died in 2003.

In my garden I have a wistaria (1984) and a yew of about 90 years , 6m high
ish. W has entangled itself in Y and grown to the top of the tree.

Given that yew has poisonous characteristics, is it possible that the
intermingling may be harmful to W?

As you may have gathered, I am not blessed with green fingers.

Many thanks,
Nick.