[bendipa]

Do all tulip varieties belonging to a particular group, eg Gregeii Tulips, flower around the same time or can their blooming time vary significantly?

[Trillium]

Because they're a shorter tulips, they will generally flower at the same time. And it also depends on your location as to the precise 'when'.

Here's a good chart on blooming times of the various varieties:

 http://www.theplantexpert.com/springbulbs/TulipIntro.html

[bendipa]

Thanks for that very useful site. The Gregeiis would ideally be in flower around now. Not too early unlike my Kaufmannianas which really are best associated with crocuses as mine bloomed early March, a little too soon for most sprong flowers..There are some fantastic varieties of Gregeiis too, and mot all od them are dwarf either.

Fur Elise looks an absolute winner if I can find that one next autumn, although it's described as a 'mid spring bloomer' whereas other Gregeiis are classed as 'early spring'