There are two plants that you are just never going to find in my garden–persicaria amplexicaulis ‘Firetail’ which sometimes goes by the common name of Bistort (really? Is that any better?) and fallopia japonica ‘variegata’ or Variegated Japanese Knotweed.
Around here, the regular version of Japanese Knotweed is listed on our invasive plant list and since it runs rampant on every roadside, I wouldn’t dream of actually planting it in my yard, variegated form or not. I’ve had one too many instances of supposedly well behaved plants running amok on me for that, thank you very much!
And even though variegated plants don’t do very well for me, I’d prefer not to take any chances. There are just too many other lovely, well-behaved plants–and native varieties–that I can choose. Why should I take a chance on something that might have thuggish characteristics?
Personally, when it comes to ‘Firetail,’ I still think it looks too much like its weedy ancestor for it to ever have a home in my garden. I spend hours pulling plain old smartweed. Why would I plant something that in any way resembles it?
But just because that is my preference (or manifesto) that doesn’t mean it has to be yours. After all, as I always say, if we all liked the same thing, what a boring world we’d have!
Gardendaze 
I did chance planting Persicaria ‘Red Dragon’ in my last garden, although with some trepidation given the family’s bad reputation (is that an accidental poem??), but it actually behaved rather well. Can get a bit leggy but otherwise I had no real issues with it. Then again, I was cutting it back regularly because of the legginess… so that probably helped!
Goodness, between us, we are starting to make these plants sound like some really bad actors (your poetry not withstanding ). Good to know that at least ‘Red Dragon’ behaved for you. And it is a pretty color as well.
Karla