Saxman writes
beccabunga wrote:

Beware - they are one of the most poisonous plants. All parts are
highly toxic.

I'm surprised they used for public display in such quantities then?

As others have said, locals are very aware of their toxicity. And they
are ideally suited for their purpose, which is to provide shade for
people travelling along the road - lots of dense growth in summer and an
ability to tolerate a fairly hostile growing environment.
Decorativeness is a bonus.
--
Kay