Most orientals are done blooming in July. Trumpet lilies are the ones that carry the show into late season.

Stargazer is common but great, Casa Blanca is pure white with great fragrance. I got some Starlight Express last year like Stargazer but much shorter. Good for front of border but you have to bend over for the great fragrance. Can't go wrong with any oriental lily.

The last to bloom are l.speciosum...particularly the vigorous 'Uchida'. These flower in August for me and mark the end of the lily season. Also available in white.

I have both 'Casa Blanca' and 'Uchida'. For me, 'Casa Blanca' starts blooming later than most Orientals, around the last week of July and lasts through mid-August. It's about 5-6 ft tall with an amazing fragrance. As Campanula said, 'Uchida' flowers in August, almost the whole month. It's also 5-6 ft tall, much taller than what my mail-order source (B&D Lilies) indicated (3-4 ft) so that I had to transplant it from the middle to the back of the bed.