Bamboo

A few years ago I foolishly planted a miniature bamboo alongside my goldfish pond.

Not only has it spread under the rubber liner and grown through it, making the pond leak badly, it has also spread along the ground with roots and pushing over a small brick retaining wall!

A week or two back, a heron stole my goldfish, so I can probably use some chemicals to kill it off, but there are tadpoles in the pond and I would hate to put my tortoises in any danger.

Any suggestions as to how I can kill it off before it covers the entire garden?

TIA