The only one you need there is that the Dogwoods proper name is Cornus.
The others you already have correct.
In Philadelphus you don't need the 'i' before the 'u'.

I wondered if they were after the varietal name. in which case the Heuchera could be one of any. These tend to be varieties of H micrantha eg ''Heuchera micrantha var.diversifolia 'palace purple'.

Cornus alba for the dogwoods but then there are different varieties.

There are several species for the Philadelphus too.

Ah, maybe, Seaburngirl :-/

Yep Seaburngirl, I was just wondering if anyone recognised the varieties.

do you know what the flowers on the philadelphus are ike. the comon double one tends to be 'virginal' or 'bride'.

the heuchera could be palace purple, but there are so many now.
dont know all the dog woods sorry.

The cornus is 'Westonbirt' or 'Sibirica'. I'd guess the Philadelphus as one of the tallest growing ones, such as a P. coronarius cultivar. Until it flowers you'll just have to be patient! Phil J