[donna]

If the bushes haven’t been damaged, then they are already being careful.

Let them play in peace.

[Excellence]

Fences make good neighbors.

[grellis]

You kind of answered your own question and didn't realize it. They planted tulips which they don't want trampled on. They'll certainly be understanding if you politely let them know you're worried about your bushes and your tenant's garden. A lot of people don't realize that not all bushes can stand up to abuse.

Sounds like you have a pleasant relationship with them. Let them know you're concerned, I'll bet they're cool about it.

[grellis]

BTW—I have two monster mulberry trees myself...yum! Worth the mess.

[Dog Gone]

Landmines are frequently suggested at this forum as a solution to anything.

Personally, I think that’s extreme. I just wanted to be the first one for once to put that option on the table.

[Grizzled Bear]

Hide in the bushes with a broad sword wearing nothing but a layer of woad. When the ball flies towards the bushes jump out with a war cry and skewer the ball.

The down side is the neighbor will most likely stop shoveling your snow.

[mmichaels1970]

Global warming is going to kill your bushes anyway.

But seriously, I see absolutely nothing wrong with your asking them to change places.