[permaculture-oceania] Plant selection question - hedge, drought-hardy, non-edible

[jedd]

 Howdi,

 I'm on the hunt for a tree that has a few qualities, viz:
 o  up to 4-5 metres tall, maybe 2-4 metres across,
 o  drought-tolerant  (incl. temps up to 50C)
 o  frost-hardy  (to -5C)
 o  long-lived
 o  evergreen

 Am happy to irrigate it for the first few years, but ultimately want
 it to survive on around 500mm / year.

 The hedgeable thing - more to do with a tendency to sucker,
 or at least cope with close planting along a row.  It'd be nice if
 the plant grew in such a way as to make it nearly impossible to
 penetrate for both man and beast.  Oh, and I obviously don't mean
 'like a rampant raspberry' when I mention suckering.

 Also needs to be able to cope with a rising soil level over time, as
 the area silts up naturally (and as I dump soil up behind it).

 Finally, it needs to be non-edible as far as livestock and native
 animals go - as roos have devastated all kinds of types of trees
 in this part of the world.


 Now .. my thoughts so far have led me to oleander, partly because
 it also has some aesthetic appeal for parts of the year.  Of course
 it's not a particularly useful plant, and indeed as I understand it
 can be tricky to deal with - you can't burn prunings, etc.  I was
 thinking a smaller (B. multiplex ish) form of 'boo, but this hedge
 will be sitting behind some B. oldhamii, and that's been a target for
 the native animals (who also eat my raspberry, olive and lemon tree
 leaves, which gives an idea as to their eagerness).

 Any suggestions for a superior choice of plant?

 Jedd.