I don't know what Canadian pond weed is, but many types of oxygenators like hornwort come with the lead clamp. I just throw them in the pond with the clamp on them. They usually come loose after a while, so if you wanted to take the clamp off that would work too. I believe you can also plant them if you want. I don't think there is a right or wrong way to handle them.

Anne

Canadian Pond weed is commonly called Elodea ('Elodea Canadensis') and is widely used as an aquarium plant, because it grows so well.
As Anne said, you can leave the metal band on or remove it, what ever you want. It can become an intrusive plant over the summer, in small ponds but can be trimmed and removed as required.
"Horton"