We have a parakeet that we feed broccoli heads. I clean the cage outside and have noticed broccoli plants where I clean the cage! I usually just throw the spent heads on the ground. Is it the florets on the heads that are sprouting? We are going to move the plants to a garden area to grow.
Broccoli Growing Spontaneously
Certified GKH Gardening Expert
Most likely, one of the heads had enough energy left to flower and produced seeds and now they are growing. It is not unheard of for some plants to make a "last ditch" effort to produce seeds, even after they have been cut from its roots. Have fun with your broccoli volunteers!