What diameter pot do you suggest for an Angel Trumpet plant?
It depends on the size. I have mine in a 20" diameter pot and it stays about 3 1/2 feet tall. If I were to put it in a larger pot it would grow bigger (which would make it harder to bring in and out).
The more important thing to consider would be if you can keep it well watered. They are water hogs. If you can water more often, you can use a smaller container. If you can only water once a day or so in summer, use a larger container.
I have a fuzzy brown caterpillar with black and yellow stripes eating the leaves of my Angel Trumpet plant. What is it? Good bug or bad?
I am not certain which caterpillar it is. This site can help you identify it:
But all caterpillars can be controlled with Bt. This article explains more:
Can an angel trumpet be divided for more plants?
There are 2 plants that are referred to as Angel Trumpets, datura (flower points up) and brugmansia (flower hangs down).
Both cannot be divided in the traditional sense of the word, but daturas often reseed themselves in clumps, so there will be several plants growing in one location. These plants can be separated. Just check for multiple stems coming from the ground and each stem is a different plant.
Brugmansias are most often propagated by cuttings. They are SUPER easy to root. Here is an article on that:
Can I keep my Angel Trumpet plants on an unheated closed in porch over the winter? I live in Ohio, Zone 5?
They are in full sun and heat has been extreme here.
Assuming that the plant is well-watered, this may answer your question:
And more here about angel's trumpets:
My angel's trumpet tree is drastically losing its leaves and branches are dying off. How do I bring it back to health?
You have a brugmansia. This article will help:
My angel trumpet gets loads of blooms on it but they fall off before they flower. What is wrong?
It is most likely a lack of water causing the flowers to fall off. They are water hogs and need lots of water to stay healthy.