The grafted WA gums have flowered well around Engadine in Sydney too.

We did a boy-prune on our red flowering one (Yes, wife and I took equal
responsibility!). It is shooting well, but some shoots also started
coming from the root stock bit. These new leaves are very rough, smell
very strongly of eucalyptus when crushed and their stems are covered in
tiny spines/fur. At first glance(touch) they reminded me of sandpaper
fig leaves.

Any ideas on what they use for the understock for these flowering gums?

Regards,
M