Idea's for a North American Themed garden

Hello everyone, This year in my garden I had the Idea to create a North American inspired garden theme, But as I'm quite a novice at this and don't really know what plants to go for I'm just wondering if anyone had any ideas of what plants i could use, and the availably of North American native plants here in the UK? also I live in North West London so any plants suited to the climate here would be super. Thanks Have a great day  

From a few articles I have read I thought Echinaceas and grasses were a hot favourite there, known as praire planting. I also believe there are a lot of dahlia fans. But it is a big country with lots of diverse climates, so you could probably try anything and it would be popular in one part of america. Cacti for texas, Palms for california etc

Thanks Kate1123 for the ideas, I was thinking of California as the Base of the theme Will I stuggle finding California natives that will be hardy enough to survie the winters here, would the Washingtonia Robusta be allright for London?

Loads of garden worthy plants come from the USA.  Trees and shrubs such as firs (abies and pinus forms) then amelanchier, cornus florida, hamamelis virginiana, liquidambar, cercis canadensis, rhus typhina, blueberries, viburnum forms and so on.

Perennials include the Michaelmas daisy asters - nova anglicae and novi Belgica plus penstemons, some iris forms, liatris, monarda, lobelia cardinalis, caltha palustris, phlox, eupatorium, rudbeckia, heucheras, heliopsis and helianthus, camassia, choreopsis and loads of hostas.

There are plants for sun and shade, dry and moist soils but you do need to check for acidity to grow some of them so google for info or check them out in the RHS Plant Selector - http://apps.rhs.org.uk/plantselector/