When and how do you prune devil's trumpets in the fall?

Answer #1 · Brent Wilson's Answer · Devil's Trumpet (Datura) and Angel's Trumpet (Brugmansia) are tropical plants but can be perennial in gardens in Zone 8-11. Otherwise, in zones further north they can be used as a container plant and brought inside when the weather begins to cool. Reason I mention both is that many people aren't sure which one they really have. These plants can be grown and formed as either a shrub or a small tree.

Where these plants are perennial, and grown outdoors, they don't have to be pruned at all...only to remove damaged or dead branches. If you want to "tree form" the plant just remove and then keep lower leaves and branches that emerge from the trunk snipped off as new one's try to emerge. If you want to grow them as a shrub, and control the size of the plant, prune in spring, just when new growth begins to emerge. How far you prune them back is up to you but, to be on the safe side, I wouldn't remove any more than say 75% of the height. Where these plants are annual, and grown in pots, they would need to be cut back before bringing them indoors for the winter. Hope this info helped.)