Hi Loosetrife, I can't remember ever seeing any that height either, I think the usual height is about 3ft, with a spread of about 12", so I would have thought it quite unusual, Derek.

Could be Lobelia tupa ?

Hi, yes that would fit with the size, are the flowers a brilliant scarlet red, or more of a brick red to orangey red, if the latter, then definitely L tupa, the other difference is that whereas Lcardinalis is fully hardy, L tupa is only frost hardy, Derek.

I have this one in the pond margins and it is about 4 1/2 ft tall definitely cardinalis too. but 6ft is rather extreme.

I purchased one L cardinalis years ago to attract humming birds. It has propagated itself all along a boggy pond edge for years and fully winter hardy, each year getting both more numerous and taller. I have never used fertilizer either only on potted plants. Actually I am 6'2 (used to be 6'4) and its at the top of my head. I guess it is growing in a super optimal area. Thank You All for your answers.

I'd love to see a photo of it Loostrife, it sounds wonderous.

If you have fish in your pond, Loosestrife, they are probably providing all of the fertilizer needed.

I will get a shot of it tomorrow but check my blog titled "A First" posted August 6 and you will see it as it was then.

The lobelia is lovely and so is your garden.