The sustainable option is to avoid hard landscaping. And planter boxes are hard landscaping.

Work with the site as it presents to you - it is cheaper and the plants will last indefinitely if planted to work with the soil of the site.

You need to know what soil you have from the outset i.e. you most likely have a sandy top soil, but most people overlook the subsoil. Looking at the photo, I would imagine that your soil could have drainage problems. If this is the case, then Correas and most Grevilleas won't work.

Natives are the best option for a sustainable garden, but like all plants, if you don't know your soil, and then don't choose the right plant for that soil, then the plant won't survive.

The retaining wall at the top is so narrow it is pointless planting anything in this. You would be better planting at ground level and choosing a plant that is tall albeit narrow i.e. a column effect. Mass planting this around the whole fence-line would give continuity to the whole site.

Where is north in the photo and where is this home?

Thank you for your comments. My home is south west Victoria in dennington. We get winds and sea salt air. The area above the retaining walls is a consistent 105cms wide. I want to screen out the back neighbour as I can see their washing line and I fear this could be the same issue for the house on the side when it is built. North orientation is what you see and most of the area at the moment has been generally shady. I dont know if thats because its winter or because the higher fence and retaining walls shades the area. I agree with you as I think we do have drainage issues as we have a number of muddy puddles on the block after a down pour or long period of rain. Much to the kids delight. Maybe I have bitten off more than I can chew here and I might have to consider obtaining the assistance of a landscape designer.

GOOD professional advice is worth every cent of what you pay.

If it was my property, I would ignore the upper retaining wall and plant at the bottom, selecting a plant that will screen from the bottom to above the height of the fence. Its also much cheaper this way.

There are numerous lily pillies available that you could consider. I would choose something like Syzygium 'Pinnacle' because of its eventual height, its adaptability to different soils and sites, and because it is relatively narrow. Its also fast growing. It is a conical grower. Plant them 1.75 metres apart or thereabouts, working the spacing depending on the length overall and then just nurture them. If you retain the the conical shape, then you wont need to hedge them - just leave free standing or trim the width a bit.

Then bring in some taller trees that will grow higher or at least as tall as the Pinnacle - I would use deciduous to allow winter sunlight in and have large garden beds under the trees linking the whole area together with lawn or lily-dale toppings or similar. Lawn would be better for the children, but will need irrigation [in summer only if necessary]. And if growing lawn under trees, you need to be selective with the lawn type considering shade, tree roots etc.

I know that people mock the use of lily pillies, but these are people who don't know what they are talking about. The knockers have grown lily pillies that are inappropriate to the position and because of their stuff-up, the whole range of wonderful plants gets canned. The right plant to the site is called sustainability.

Councils/government are opening up a lot of areas that were once considered wet-land. So a lot of these new subdivisions do have drainage problems, and buildings with their footings increase the movement of water, increasing the drainage issues. Small gums, like the Eucalyptus leucoxylon ssp megalocarpa is a wonderful tree for soaking up excessive moisture. This is also worth adding to the tree mix, especially to shade western windows.

Good luck with your project.

Thank you for all your information. It has been wonderful and I will certainly be taking your advice. I think I will invest in a landscape designer for some initial assistance. Once again thank you.

Good luck with it all. It's a wise decision.

My dog eats the LillyPilly berries.

Thats good to know, thanks for that. I have dogs so I would not want them to eat the berries.

Maybe it's ok? The birds eat lots of them, and I think you can make jam? Timandra?