Sacha wrote in message

We have S. confusa, S. hookeriana and S. digyna 'Purple Stem', so it's
hard
to tell which is smelliest. But the one we picked and brought into the
house is confusa. I do think air temp. must have something to do with the
release of scent, and perhaps light levels, too. For example, the
Brugmansias we have seem to release the scent most powerfully at about 5pm
every day and the Impatiens tinctoria doesn't really perform at all unless
the sun is pretty strong.
--

A number of plants smell at certain times of the day and at certain
temperatures/sun levels, it is supposed to be because that's when their
natural pollinator is about and active. So you only get night scent from
moth pollinated plants etc....

Whilst on the subject of scent, have you noticed that Spray Carnations etc
bought from a florist have no scent these days?
I tried an experiment a couple of years ago and planted various off-shoots
on bunches I bought and raised them to flowering on the allotment, in the
open, wonderful perfume! So it's because of the growing conditions not the
variety.

--
Bob

www.pooleygreengrowers.org.uk/ about an Allotment site in
Runnymede fighting for it's existence.