it can be either. If in the autumn they will flower mid spring. if planted in spring they will flower in late spring early summer.
they don't like getting overly wet so grow in free draining compost.

Thanks Eileen. So the cold weather won't bother them?

the RHS says they are H4 so hardy down to -10 centigrade. But like most bulbs/corms its not so much the cold but the cold wet.
I'd probably grow them in pots in a cold frame/unheated greenhouse then plant out where you want them to flower in the spring.

That's a good idea Eileen. They are only good for 1 year according to what I've read online.

I had some that gave a good plant for about 4 years, they were in a large container. The hard winter's of 2010/11 put paid to them.

I planted some last year I will wait and see if they re-emerge this spring.