I don't believe that there are any species of lavendula native to australia. Perhaps people are talking about westringia fruiticosa, a purple flowering, easily hedged bush from NSW. nearly bullet proof.

Thanks Nathan. I thought the westringia are usually known as rosemaries. But then I also didn't know there were any from the east coast.

It's all seems to be a bit of an adventure at the moment, with so many patented plants and grafts coming into general retail nurseries that the staff don't really know what's what. And people say "native" the way advertisers say "natural".

Oh well. Thanks again. I'll keep looking - I would like the soft grey foliage with purple flowers if I can find it.

I must admit the "Native Lavender" has also thrown me as to what it is you refer to. The last line of you message (above) you mention soft grey foliage with purple flowers. If this is the case, why not try something that is 100% native eg Dampiera purpurea or sericantha, or maybe a Thomasia. There are a myriad of Native shrubs that would suit your purpose.
A visit to a Native Nursery would be best if you want to discuss either plants or growing into new soils, with Native plants.

If you are after a silver/gray foliage and purple flowers look at: Eremophila nivea

But it is best grown grafted on the East Coast. Most nurseries have it.

Ours is around 2 metres high - growing in a hill of pure sandstone sitting on top of clay - garden is in Ryde area

Here is a link that might be useful: Eremophila nivea Chinnock

Try Vitex trifolia or V. ovata, these may sometimes be referred to as native lavender.
They have blue flowers.

Roy

Having discovered that my daughter thought my native Plectranthus (Cockspur flower)WAS lavender, that's the one I'd go for. There are a lot of species, some of which have silver foliage, and some have delightfully aromatic leaves. They all have spikes of lavender coloured flowers, which make them very good cottage-garden subjects. They're as hardy as old boots, too.
I don't know whether you would be able to get them from nurseries, which do seem to be fixated on woody shrubs (these are herbs, and very easy to grow from cuttings or rooted pieces). I'm sure local SGAP / Australian plant society members would be able to give you some. My own are a very varied lot, resulting from original plantings of seven or eight species which have hybridised and become decidedly motley. You'll probably find the same thing going on down there, with a lot of choice to get just the shape, size, leaf perfume and colour that you want.
Trish

Maybe someone was referring to the lavender called "Sidonie', supposedly bred in Sydney. It's a scrappy kind of plant I reckon- but nice colour dark blue-purple flowers on l-o-n-g stalks.

Thank you so much everyone. I'm not quite there, but getting close.

First, I've found one nursery website that calls Lavendula sidonie "Australian Lavender", which could easily become "Native Lavender" in conversation. However Google also turned up a Qld local govt report on dune revegetation that actually uses "Native Lavender" as a common name for Vitex trifolia and V. ovata. So I guess that might answer the naming question: congratulations to Roysta!! However I think a dune plant probably wouldn't be too happy on our glorious red clay, so I've ruled it out for this garden.

I have some (presumably grafted) yellow flowering Eremophila in the back yard that are quite happy with the soil. What's more the people 2 doors up have a flourishing Erimophila nivea, though they don't have my cement additives. I remember thinking about an Eremophila about 6 planting plans ago - maybe I should have stopped then?

The Plectranthus sounds ideal for a tight corner where a retaining wall meets the front path. I've got a problem with the name though: do you think it would be P. argentatus? My Gardening Australia Native Plants guide describes it as "Spreading species from Qld and NSW. Silvery gray, softly felted, slightly hairy leaves." It also says there are about 25 Oz species, but doesn't name any others. I've found references to P. parviflorus as "Little Spurflower", but FloraOnline describes that as "non-aromatic".

Sorry this is so long. I do appreciate everyone's help, and no doubt I'll stop dithering and/or panicking eventually. Or very soon: the contractor is ready to order plants.

Thanks again,

Ghoti

a bit of cement isn't a problem for eremophilas - they actually like a relatively high pH. Is your name really 'fish'?

There's nothing wrong with Eremophilas, they're fabulous.
Go for them.

Plectranthus argentatus is certainly worth growing. It is relatively large among the Plectanthri, - meaning thigh-height. Its large silvery leaves are a bit smaller than the palm of your hand. It is unusual and therefore valuable in a landscape sense in being one of the few silver-leafed plants that will grow in the shade, and therefore lighten up a gloomy corner. They also do well in full sun. The flowers are pale lavender-colour. The leaves, however, are not aromatic.
P. suaveolens is the scented-leaf one that you are most likely to be able to buy, I think. Silver leaves, lavender flowers, but a smaller plants and definitely wants good drainage and not much water. Win points for growing a rare and threatened thing.
Plectranthus blakei is my favourite for flowers, which are in big terminal spikes and a good strong shade of purple. The stems are red and the leaves green. A thigh-high plant, taller than it is wide, so best planted in quantity for a good show.
There is an aromatic green-leafed one which grows at the Bunya Mountains. I wish I knew its name as it is very attractive dense thing with the shape of a rounded thigh-high shrub. I have another problem in being too ethical to pinch a cutting from a national park. More fool me, I suppose.
P parviflorus is not worth the trouble. A scrappy-looking plant, but perhaps the commonest in the wild.
Other names are:
P. alloplectus, 70cm, rare and threatened, from Moreton district. violet blue flowers, no fragrance
P. amoenus, dwarf, aromatic, S. Qld, hairy leaves green above and silver below, lilac-blue flowers, flowering well in light shade.
P. gratus. Strongly aromatic. Can't remember which one is it in my garden, but I think the leaves are green.
P. graveolens. silver leaves,with a good strong scent. 1m Violet blue flowers
P. nitidus. Probably not worth the trouble, as not scented and not remarkable flowers
P. spectabilis. Only lightly fragrant. Grow this one for the showy flowers in big fluffy heads. Green leaves with purple backs.
P. torrenticola. Dwarf, silver leaves, fairly fragrant, light purple flowers.
Am I being ambiguous here? In all cases it's the leaves, not the flowers which are fragrant.
There are also a few introduced Plectranthri in Australia. One of them is an old fashioned thing which Queenslanders used to grow in their gardens to use in cooking. It was called "All-purpose herb", but I haven't seen it for years. I think it originated in Ceylon. Our gardeners are too strongly influenced in their herb-growing habits (as in so much else) by imported gardening books, I think, and this has just gone out of fashion. It has a good strong sage-and-thyme flavour, as I remember. There might be good native ones for culinary use, but I haven't heard of anyone using them, and am reluctant to experiment!
But where to get all these lovely plants?
I still can't do any better than suggest your local branch of the Australian Plant Society, which might put you on to people who...

Trish thank you very much for all that information. That must have taken you ages.

Plants were included in the price of the job and I've been in a complete dither trying to get this silver-leaf & scent plant from the landscaper's suppliers. I also got myself in a muddle over where to put it - somewhere between plans 15 and 28 it moved from beside the steps to... oh well never mind. I thought I'd settled on P. argentatus, but on Thursday night the landscaper rang to say it wasn't available and would P. static-spit-are-you-there be all right. Like a dill I said yes, but it turned out to be not all right at all. I still don't know what it was because the label just said Plectanthrus and it didn't seem to fit any of your descriptions.

Anyway, the plants have just gone in and the mulch is going down now, and I've left spaces for the silver leaves. Based on your description, I think it will be two P. suaveolens, one on either side (sort of) of the entrance in raised beds so that the soil is a bit below knee height. But who knows what I'll do when I get to the nursery?

In my original post I was thinking of two plants either side (sort of) of the western garden in front of a north-facing wall, with one of them also being beside the front steps. I've now got Boronia megastigma lutea "Australian Beauty" (yellow flowers) there, and I'm quite sure that's really stupid because they're the hottest spots of the whole property. But we'll see.

The landscapers should be finished tomorrow and there's rain forecast for the weekend. I think I'll just give myself a few weeks to calm down and get acquainted with what's here now, and then go to a specialist nursery for the silver leaves. It's a bit of a funny way to go about it because they'll be strong feature plants, but this is by far the biggest garden project I've tackled and it's been quite a challenge. I like my garden changes gradual.

Thanks again. I'll get in touch with the Australian Plant Society too.

Ghoti

PS I'm also interested in Oz culinary plants, but that'll probably have to wait a couple of years. Hemphill now sell Wattleseed as a spice and I think they're experimenting too. It's coming. Thanks again.

Are there succulent Plectranthus enthusiasts still out there? P. argentatus is popular and easily identified, but other Australian forms are little known here. S. African Plectranthus are more accessible in N. America.