brugmansias

I grow them, grew about 60 this year and have been growing them for several years I can probably answer most of your questions,first of all when brugs start flowering and the petals start pushing through the calyx they are coloured green/yellow regardless of their final colour they gradually turn white as they open and start to change colour it is not uncommon in fact quite usual to have what appears to be several coloured blooms on one plant.You cann't by seeds of a particular cultivar (with the exception of Arboreas, Sanguineas and their crosses) they are reproduced by cuttings(clones)They will flower in pots but grown from seed need to reach a phase in their development (that is the main stem needs to fork after this the flowers will develope above the fork)this can mean the stem can be 4,5or6ft tall before this happens on the other hand any cutting taken above the fork and grown on is capable of flowering right away even if only 1ft tall,I had a cultivar "apricot queen" in a 7"pot with nearly a dozen blooms the pot was on a stand to allow the blooms to hang down they were 22"long.Most brugmansias are self sterile(will not produce seed)except the 2 varieties mentioned above but are easily cross pollinated the seed pods are various shapes some resembling small cucumbers holding 200+seeds each seed has the potential to be a different plant some retaining properties of the female plant some of the male I have had some plants grow pink some white out of the same seed pod.Pink ones do have scent some varieties have more than others and of course the scent is more dominant early evening/night the reason being they are normally pollinated by moths and night critters in the countries they come from.