A botanical park would be a good thing to start...

...I thought to myself recently. We have a large collection of plants and I am a total plant fiend. I don't just love one sort of plant, there are all sorts of wonders out there. Ah, so a little thought but with a lot going for it in the long run for biodiversity and as a demonstration of what can be grown in dryland areas.
We need land. This is of course the hard bit to do. Dryland is fine but we'll find something we like, and we will get there.

Pictures of public gardens such as Huntington Gardens in Southern California, especially the desert section really inspire how I'd like a garden to look. Of course, you then need sections for Banksia and Hakeas, the dryland sustainable agriculture/permaculture section, an arboretum of useful and edible trees... and 200 years to see it mature. sigh.