By Barbarak
North Yorkshire,
United Kingdom 
Is there any way of finding out which perennials die back due to cold weather and which die back due to lack of daylight hours? We have had a prolonged summer up here and there are no signs of Autumn yet and do Autumn flowering 'crocus' , schizostylis and amaryllis belladonna need cold weather to flower? Thanks.
27 Sep, 2016
Answers
I'm in the midlands and my colchicum are more or less over....
They flowered even though its been warm so I guess at day length
27 Sep, 2016
Amaryllis belladonna doesn't need cold to bloom, but hot, dry weather in summer often improves flowering.
28 Sep, 2016
not so sure really but our colchicums and schizostylis are flowering. the latter is initiated by light wavelength so my understanding goes. the flower for the colchicum is laid down in the spring when the foliage is doing its thing.
27 Sep, 2016