Yup, thats why I mentioned "rough and tumble".

It is impossible to cultivate here (I've tried multiple times).

Any ideas as to what is the problem @dbarron....too dry?

Too hot...it melts ;) (quite literally) This is a plant of the arboreal mountainous North.

Epilobium/Chamerion angustifolia has a very wide native range and adaptability to a very wide range of habitats. You can find it growing all over the US except in the extreme Southeastern or Southwestern portions of the country.

Chamaenerion angustifolium ==plants.usda.gov. Doesn't look that widespread to me ;)

And that about typifies where I've seen it.

I quite like this plant. Makes the roadside ditches beautiful in mid-summer. My attempts to grow it, even in my 'rough and tumble' parts of the yard have mostly failed. It doesn't last long and never really spread. Perhaps it's my poor, sandy soil.

With the wide native range, it might be best to source plants grown from a local seed source if possible.

From the USDA: Fireweed is widespread in the northern US and Canada from Labrador to Alaska. In America its distribution extends south along the eastern mountain chain into N. Carolina (Myerscough and Whitehead 1966) and in the west down the Cordilleran range into California and New Mexico.

Makes the roadside ditches beautiful in mid-summer

I for sure see lots of "Joe Pye Weed" in ditches in our area but I'm not sure I recall seeing any "Fireweed".

Well I can definitely say that even your map GG, those states are mountainous and it's probably found at elevation.

This from the Prairie Moon website could be the other part of my problem. I tried planting them in those rough and tumble areas that were already growing with rough and tumble plants like Solidago.

The one thing it can't handle, however, is competition. If other species are allowed to grow in and over top it, Fireweed will quickly succumb.

" The one thing it can't handle, however, is competition. "

Does not appear to be an issue here :-) Since it is considered to be a weed in the PNW, it seems to have NO difficulty popping up in the middle of other plantings!! It will even seed itself into planted containers and if you do not stay on top of it, it can rapidly take over a perennial border.

I planted bare root fireweed and like Debarron I was not able to cultivate it. I think it was because it was too hot. Monarda citriodora is easier for a plant with similar height and flower color imo. But fireweed might do better up in Canada?

But fireweed might do better up in Canada?

I think I will try one plant this season...it will be an 'experiment'.

It is usually known here as Rosebay Willowherb and is a common weed/wild flower forming huge patches on waste gound and along railways. If it likes your conditions it will quickly self sow via the wind blown seeds. There is a white version which I believe is more docile.

It should do well. According to Grow Me Instead, fireweed is a recommended alternative to Dame's rocket, Hesperis matronalis, which IS a listed invasive species in Ontario.

Based on that, one can assume the plant behaves quite differently for me :-)

Fireweed seems to do well in Minnesota so it should do well in Canada. When I think of alternatives for Dame's rocket the plant that comes to mind is the native purple rocket Iodanthus pinnatifidus.

Iodanthus pinnatifidus

forming huge patches on waste gound and along railways.

So @floral_uk z.8/9 SW UK...sounds like the same locales that invasive buddleia do well in.

Epilobium angustifolia grows in and around my property filling spaces between the native hazelnuts, does not bloom for particularly long and seeds out into cultivated beds and must be promptly removed for its aggressive spreading habit. It's fine for naturalized planting, but not something I'd set my heart upon! Where as epilobium latifolium (below) knocked my socks off seeing this dwarf beauty blooming among the alpine flowers of Jasper National Park. I acquired seed and grew it as a front of the border plant that flourished for several years, the rather large stunning blooms are produced for about a month or longer, photo does not do justice!

Epilobium latifolium, photo from the net.

Excellent @FrozeBudd_z3/4. Thank you.

I am very fond of epilobium angustifolium and have had many attempts to grow the beautiful white flowered version (E.angustifolium album). Evidently, it is far too dry where I am, and it dislikes my soil...whereas I have no problems whatsoever growing the weedy tetragonum and parviflorum. Or somewhat stunted versions of e.hirsutum (codlins and cream) which is an enthusiastic grower around my wood. I vaguely recall trying to grow a cream coloured, procumbent variety which was also a fail. And a daintier version of hirsutum - e.dodonaei which was also not very successful.

Where I grew up (in the rainy NW), rosebay willowherb was always associated with disturbed ground and bombsites - very much a symbol of urban renewal