What to with my Lillies

Hi, My clematis Diana is flowering. Slight if not vast exageration . It has one flower.

 

Jean, if it has a flower it is flowering.

 

It is probably shivering as well, but it is flowering.

 

I had a Rhododendron in flower twice this year in the western isles (cunningham white) so again the seasons are all to pot however the best thing that i have found to do is NOTHING leave nature to its own devices and the plants will adapt.
if your lillies are bulbs then by all means cut them down and store dry in the green house however i would be tempted to plant them under ground as they may well come up again next year at the right time.