Q.How do Pride of Barbadoes plants multiply?
I have a blooming Pride of Barbados (Is it also known as Mexican Bird Of Paradise?) This AM I discovered a small leafy plant a couple feet away from the Pride of Barbados. The leaf looks exactly like the leaves on my blooming plant, but it is just one leaf growing out of the ground. Is it possible the large plant sent out an underground runner to produce a new plant? Thank you.

Certified GKH Gardening Expert
Yes, these can propagate by roots, or by seed. It is possible that there is a shoot from the main plant, but it is also very possible that a seed has come up!
You can care for it until it is a little bigger, and then transplant very carefully to another spot, or a container.
This article will help you to care for these plants:https://www.gardeningknowhow.com/ornamental/flowers/bop/bird-of-paradise-an-exotic-flower-like-none-other.htm