It looks more like a larger variety of Water Plantain. I don't know much about it, but positively identifying what you have is key. I am leaning more towards it being a benefit rather than something to be worried about. These type of plants (arrowhead, plantain, pickerel weed, water canna, etc - emergents in general) do not grow in very deep water and make nice shoreline greenery among other benefits.

If it is Plantain...I would welcome it in my pond, but I have a more natural goal for my pond compared to some who strive for a more mowed and manicured pond. Figure out exactly what it is and we'll go from there.

Fish on!,
Noel