Maybe if you made it darker/more boreal in colour? Something like the northern Canadian Shield? That's fairly swamp-ish territory, and probably on an equivalent latitude. Tundra land itself is pretty marsh-like in warmer months, for that matter! As far as I'm aware. Although, for that matter, how would a swamp exist in amongst all those mountains? No matter where the wind is coming from, you'd get major rainshadowing, I'd think, and most run-off would go on the windward side of the mountains. Just thought of that as typing this, lol.

Glad you found it of use. I'm not a geographer or geologist (as much as I enjoy those subjects) or anything but I've spent a lot of time working on realistic climate for maps of my own!