Gentiana sino ornata, Schizostylis coccinea, Gentiana farreri, Nerine bowdenii, Cyclamen alpinum are the only things I can think of, and they're not really perennials, mostly bulbs, and may flower earlier, in October, instead. Otherwise its berries on things. Yep, you just clear up - its "bring out the dead" time, too depressing to think about ...

Some roses are still in bloom then. Japaneses anemones might last till then. There is a knifofia that blooms very late ,into November. Our black grapes are still on the vine then, if the starlings don't get there first.

many of the chrysanthemums and asters are still strutting their stuff too. pulmonaria rubra often gives the odd flower too. If it is mild many fuchsias and Dahlias are also flowering.

Sedums and some hardy fuchsias still.
Michelmas daisies maybe...

I had tulbahgia vilacea flowering in November too.

Thank you everyone. I have already found that dwarf dahlias, begonias and hardy fuchsias are all just about capable of making it to November, or at least the first half of that month. That is why I always grow them. It depends on the weather. I have tried schizostalis and nerines before, but found they flowered in October for me, while my begonias and fuchsias were all still doing strongly into early Nov. So I didn't really need them. I'd be interested to know which sedum varieties and short aster and chrysanthemum varieties flower into Nov. It is the time of year when I decorate my garden ornamentally with pumpkins. I have also bought two darylensis heathers which claim to flower from Nov. I hope they prove to. All the promise of summer is ahead of us. Our bedding is going in. But we don't stop planning ahead, even beyond this great season, do we. It is what we are as gardeners.

I also know there are true crocus and snowdrops that flower in Nov so worth seeking them out.

Yes, very specialized things. They must need several years of careful nurture to get them to build up to make a small display.

I have Crocus sativus and it starts in october and lasts for a few weeks. I have found they multiply readily.

In November last year I had the following in flower: Chocolate Cosmos, annual Cosmos, Dahlias, Chrysanths, Salvias, Lychnis coronaria, Gaura, Zinnias and Solidago.

Well done to you.