The parlour palm is the most reliable palm for indoors .. Plants add exponentially to the indoors effect and personality, as has been said many times over, however as with anything, ideally should be placed/chosen tastefully and not in a hodge-podge or messy looking fashion. Unhealthy looking plants are particularly unattractive ..

Not sure how it would go in Brisbane but what about trying a conifer? They grow fast and very tall. You can shape them or leave them natural. They are plain and certainly not tropical. Maybe speak to a local nursery and find out if they would grow in the sub-tropical climate of Brisbane first, as they are usually in colder climates (Sydney and south). Leightons Green Conifer – Leyland Cypress http://www.evergreengrowers.com.au/shop/hedging-screening/leightons-green-conifer-leyland-cypress/ Your quite limited if there's not enough sun and you dont use bamboo or tropical plants. Many other screening plants or hedges wont get tall enough for that space and climate. I hope you find something.

Congrats on choosing blocks for your garden bed. If you're looking for trees, I suggest considering a maple tree. They grow nicely over time, providing shade and privacy. I recently moved to a new house myself, and I'm also exploring plant options. Back in my hometown, we had a reliable tree service that helped us with planting and maintenance. Maybe you can find something similar in your area. I came across this website, https://www.deepdale-trees.co.uk , which might be helpful for you. They offer a variety of trees and services.

I love to mix artificial plants with real plants. I'm not a green thumb, so this helps a lot. There is a business in Perth called Everlasting Greenery, website http://www.hostwin.com.au They stock a huge range of artificial plants, trees, bamboo, flowers. I checked the website, they ship all over Australia. Please see attached photo of one of the plants, mixed with my real plants.