We have a number of different Erythroniums in the garden - mainly revolutum and dens-canis. We also have S. canadensis, but unfortunatley have lost a beautiful double form.
We have tried Trilliums, but with no success - and they are expensive to get hold of over here. Never seen as much money thrown at a garden as at the Queen's "Savill Garden" - amongst other spectacular things it had a double-sided Trillium border, about 50 yards long and 12 feet deep!