Had a run in with a big one today. Was out planting the last of the Daylilies in an area surrounded with Viburnums, Magnolias and roses, where I have found other PM's hanging around (lots of hummingbird plants here).
Anyways, I was doubled gloved thank goodness, as when I went to pick up the trowel I had laid on the ground a huge PM was on the handle. Fortunately, he didn't get to take a big chunk out of my hand, like one did a couple of years ago when I was cutting down, without gloves on. My hand swelled for a week then!
That's my story and I'm stickin' to it!
I think they are very aggressive, even to US!