Angel's trumpet--flower faded in two days

Anyone growing these (Brugmansia, formerly was datura meterloides--spelled from memory)
I've got one growing (all white flower). I seeded it a bit late (May 20th) but it has grow quickly. It bloomed its first flower 3 days ago but I only got to enjoy it for a day. The plant was wetted down from a thunderstorm the night after the flower opened. The next day it was drooping down, mashed closed. After that it started browning throughout the petal tip and when I touched the 8" petal cone it separated from the bud.
Is this normal? Are the flowers that short lived or was this because of the rain? Should I cut the petal-less flower base off to avoid a seed pod and encourage more growth.
I haven't been fertilizing this much. It is growing in a pot of equal thirds mix of composted manure, peat & perlite. I've got two more flowers growing now on it and it looks like a bunch of branches are starting in the V of each existing branch.
I am hoping to overwinter this plant indoors this year (it is Zone 9-10 I believe) and repot in a tub for next years growth.
some side info...
We are experiencing occasional torrential downpours (2 inches in an hour). We have already reached August's average rainfall. This plant is more sheltered since it is against the house wall facing SW and under an overhang so it doesn't drown like many of the other plants do.
This plant has also been attacked twice by bugs chewing the leaves which is a shame cause they are supple and velvety to touch and very attractive. One left yellow eggs everywhere and tiny yellow inch-worms. Another were colorful Orange and black beetles. I think they were stripped more than dotted. I have been cleaning them off by hand.
DiGiTAL ViNYL (no email) Zone 6b/7, Westchester Co, NY, 1 mile off L.I.Sound 1st Year Gardener

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