Hello

I think I'd use palms - specifically Golden Cane palms. They grow quite tall but are shallow rooted, so should not cause trouble with plumbing or foundations.

Then an under- storey of other heat tolerant plants - bromeliads, parlor palms, tropical impatiens with liriope softening the edges of the steps.

That way you would have something to look at on the way down the steps, as well as from the top floor rooms.

Cheers

Thanks. Do you know how tall and wide these palms grow and whether they would be suitable for Melbourne weather?

wild orchids they do well in full sun in pots

birds of paradise

kumquat trees will give you white flowers and fruit :)

The soil there is mostly fill but the beds have garden mix in them from the nursery. The fill underneath them has been worked with gypsum too. We would plan to extend the beds up the hill so to speak and again prepare them with gypsum/garden mix. I really like your idea of a smaller tree with the foliage at the lower trunk kept clean with a foliage canopy up higher. Can you suggest any smaller trees that would work like this? I wonder about Chinese Elm??? What do you think about this option.

Any imported soil will cause problems with the longevity of plants that you choose. You are always better off working with the existing soil on the site.

Because of changes, I would suggest that you consider getting a professional in to have a look at that site. You have a slope towards the fence which is going to cause a problem and the garden bed that you have constructed only looks as though it is about 50cm wide. This is nowhere near wide enough to get any plant to grow to fence height. Unless you grow bamboo which is expensive and wont like the imported soil. And even then this plant will increase beyond 50cm - even the clumping forms.

As for the Chinese Elm - these can become massive trees. Taller shrubs, like Callistemon pallidus could have the stems trimmed and retain the canopy and being native will be more tolerant of soils and conditions.

Professional advice is needed here. And get an older person who has had years or experience and is a horticulturist.