Many aquatic plants can have the same treatment. Stem plants will grow bushier if pinched out. Rosette plants on the other hand, where all you've got are individual leaves growing from the bottom, are much harder to force in any particular direction. In the same way that you can prune roses but not rhubarb, you can prune Bacopa but not Amazon Swords.
(I know you can force rhubarb. You could probably force Amazon Swords as well).
