Lilium speciosum is a lily that blooms as late as September in some places. Mine usually blooms in mid to late August, and my favorite, lilium speciosum Uchida, is in bloom now, has been in bloom for over a week, and still has lots of buds. It needs acid soil to come back year after year, so I add some soil conditioner to the planting site, spray with Ironite, and it comes back taller and stronger every year. I put all my lilies that need this treatment in one place. The other I have that needs it, which already bloomed, is lilium auratum platyphyllum.
A wonderful late blooming lily