Hi Ida, I’m sure other Houzzers will offer up some suggestions :) I just wanted to share with you -my grandparents lived on a main road in Brisbane... two lanes inbound & two lanes outbound... it was heavy traffic most days so you can imagine the noise. Strange thing is... after living with my grandmother for 6 months, you don’t really notice the noise anymore... sort of like a non essential sound your ears don’t need to bother with listening out for anymore if that makes sense? One thing to bear in mind... the dirty black dust from heavy traffic, made the window sills & window screens in the front bedroom/loungeroom as black as tar which was a pain to keep clean. That said... they loved their home & lived there over 60 years :) congratulations on your purchase & I hope you can implement some beautiful hedges, gorgeous plants & timber screening for your front yard ... even if it’s not technically a noise barrier... the greenery will be beautiful :)

No I’m not in Brisbane. Bunnings generally have a limited selection of the more popular natives. Your best best bet will be a local independent nursery. They can order in and give good advice. A lot of native nurseries also sell online and deliver interstate.

I'd normally say go for a row of ornamental pears but I think it might look funny given your row of connifers as you don't want to look boxed in. I'd think about disguising neighbours with a single largish specimen tree in that side with lots of underplanting. You can't realistically block out all unattractive parts of outside your yard and what you really want to do is create interest in the foreground so it draws the eye in. Or else do the row of pears but create a bed in front of connifers and plant variety there (bearing in mind how connifers change soil acidity).

The tree would be to replace the silver birch in the photo which doesn't provide much shade.