Wow. Um... what? lol I clicked this thread in hopes it would describe what its title contains. Salmonberries and fireweed? I may just be an uncultured east coaster, but I have no idea what they are. I'm sure a simple google search would help me, but I'd rather ask you, since you are thinking of including them in beer. I've heard of chamomile use in a wit. Not sure of its flavor profile, but I've heard it done before.
So, what can you compare salmonberries and fireweed to? flavors/colors/intensity? Very interesting choices, and I support it... just cant advise you fully since i dont know what those things are lol
However, I will give you a few tidbits. There are a couple ways to do fruit. pastuerize, sanitize, freeze. Freezing doesnt actually kill all bacteria, but I have found that it works well enough for store-bought fruits that have been through pesticide/radiation to really kill bugs (...I can feel the hippies eyeballing this line, getting ready to pounce...). Sanitizing with your standard concentration of fermentor sanitizer of choice would work great, I do recommend an additional rinse in sterile water to really lose the traces of sanitizer, though (even though small amounts can go undetectable or perhaps even act as a yeast nutrient (IIRC star-san has tons of support), I'd rather have no chance of off flavors). Pasteurizing can either take place in a seperate pot, or if you want to throw the fruit in at the end of the boil. Heating the fruit like this purpotedly affects the way it contributes to your beer. I personally don't use this method, but you may find it suitable. Also, there are different thoughts for the form of fruit i.e. whole or cut or pureed. Search around, find what you think sounds right for your own methods. I tend to use whole smaller fruits, i.e. blueberries raspberries or mulberries, and I will cut my strawberries in half.
Good luck on your endeavors!