How long or how often does something have to happen for you to learn from the experience? I assume you planted this thug in good garden soil? IF you are planting it in very poor soil, it may well remain a good garden denizen and stay where you put it. If it's again in good soil, you may have a permanent boarder - I have an artemisia I have been evicting for 4 years - it keeps popping up in the middle of my daylilies! If you ever fall for Eupatorium coelestis/wild ageratum, be warned that it is a major thug in good soil, spreading up to 5'! Many of the wildflowers are best kept on a very lean diet.

after a similar experience, i replanted mine in a pot sunk in the ground. i still get a few plantlets nearby, but nothing like the first assault. i do love the flower color!

there is a wretched aster that i planted about 5 years ago that i pulled out at the same time i pulled out the bog salvia...and i still find it creeping around the garden...that aster was banished out of the garden altogether at the time.

live and learn

You can control it by pulling runners but I agree with inthegarden that putting it into a pot would be the easiest way to deal with it. Bees love bog sage, it blooms all summer, but it is aggressive.

I let my bog sage wander around the front bed and just pull what I don't want. It comes out pretty easily and I like how it works as scrim and as a mingler. Sometimes it makes wonderful combinations I hadn't considered, and I like to be surprised.

Dryness really helps to control bog sage. I had mine in moist soil and had to spend a few hours one spring eliminating it in a bed where it had taken over.

Mine's in fairly heavy clay and it's spread has stayed put at about 4' for 4 years or so. I do dig from the edges for the swap, but that clear bright blue is just so great, i don't mind a bit. I let it thug it out with an agressive purple aster and 'black & blue' guaranitica, which for me is petty thuggish, too. I like the 2 blues mingled. If i ever decide to get some going in back, which i very well may, i'll probably confine it in a pot.

I have the bog sage in the moist area at the bottom of my sunny slope...with a B&B just up behind it, too! I have an 'Adonis Blue' buddleia, agastache 'Blue Fortune', blue penstemon, caryopteris and amsonia for the blues on the slope, too. I have some yellow snaps and coreopsis for some contrast. I'm still working on the moist area, but have some blue nepeta subssellis at the feet of the bog salvia. When we have rain, the moist area is a rain garden and it drains slowly down to the drystream bed.

The runners are very easy to pull. I have lots of space in the moist area, so I'll just keep it off the dry slope.

In moist good soil it will gallop away. Mind you, I still keep it, because its as everyone says --- how can you beat that color?!?!? I keep mine in a pot, sunk in the bed to help with the control issue. If I had the right location, I'd probably let it run wild.

Wonbyherwits' bed sounds like a beautiful place.

I've left it on its own a couple of times. It has always managed to go somewhere I absolutely could not stand for it to go and gets confined again.

I planted it for the first time abt a year ago on a dry clay slope. Loved the blue and checked for it today and it is returning, Yay... but then I love pink evening primrose, mint and lemon balm too, so what do I know, lol...