My absolute favorite perennial for late October, early November? Amsonia hubrichtii, common name Willow Blue Star (though I've never seen anyone actually use that. So I think in this case it's Latin or nothing.)
- Hardy to Zones 3-9.
- Sun or partial shade, but there's better bloom and height with sun.
- Grows to 2-3 feet high and wide.
- Flowers May-June. Gives another major show in fall.
- Established plants are reasonably drought-tolerant.
- Some sources advise cutting it back to 6 to 8 inches after the blooms have faded to make it bushier and to prevent flopping, but I don't know anyone who does that and I haven't found it necessary.
- Sources also say it can be divided in spring or fall but that it shouldn't need it for many years.
- It overwinters better if not cut back to the ground in fall, so wait til early spring to do that.