Hi Carol,

Oh, that's truly unfortunate. It's very likely to spread throughout the lake shore. I'm not a lawyer, so I can only speculate. I don't think there's a whole lot you can do about what people plant on their property.

Some thoughts:

• You'll want to learn to recognize what loosestrife looks like as a young plant, keep an eye out on your portion of the shore, and remove any volunteers as soon as possible.
• Some lakes have associations whose mission is to keep it beautiful and useful for everyone. If you have one, that might be a good question for them.
• There might be some regulations on this (federal, state, and/or local), so I'm going to check with some of my natural resource colleagues. It may be illegal to plant or propagate an invasive species like this.