Arnold asked " Do you think that the intense fragrance is related to the volatile oils and that they are more active in higher temps?" It seems reasonable, doesn't it? Different oils have different evaporation/boiling points, and it stands to reason that if the crocus is producing different oils, they would disperse at different temperatures. In fact, I wonder if plants which do produce different fragrances are not disclosing a bit about their history of pollinators. It may well be that the different fragrances attract different pollinators. The dominant fragrance may well be the one which attracts the currently dominant pollinator. The secondary fragrances may well be ones which attract secondary pollinators; and to take it a step further, those secondary fragrances which do not correspond to any current pollinator may indicate that another pollinator which no longer plays a role once existed. It's as if a bit of their evolutionary history is expressed in their fragrance! Anyone interested in investing (stocks, bonds, futures - that sort of investing) would benefit from an acute understanding of the survival scenarios of even something as seemingly inconsequential as a crocus. Among other things, they're all experts at hedging! Jim McKenney Montgomery County, Maryland, USA, USDA zone 7, where a small investment in Jane's crocuses has paid off handsomely in enjoyment this year.