Tis the season for novice dyers everywhere to be surfing the web and coming up with some pretty lousy dyeing information. This forever turns them off from dyeing.
A note on dyeing with berries, with the exception of pokeberries, and this requires a special technique, all berries are fugative dyestuffs! Fugative means the color flees, it does NOT stay on your fibers, no matter the mordants, chemicals and spells you chant over the dyepot. Sorry but it isn't gonna happen. So save your berries for pie or making jam.
Now with that said, you can take the green shoots of the blackberry brambles and cook them up for a lovely green color. Just don't leave them to soak in a rusty wheelbarrow for a week like I did. Many of the berries that are out there have vines, canes or roots that will actually give a color that will last. But the color will not be the same color as the berries, usually it's yellow or some variant thereof.
NOTE: Strawberries fall into the same category as other berries. Oh and while I'm at it I know that purple mulberries will stain your favorite white shirt/blouse/suit/car purple, but you need to apply Murhpy's Law of dyeing here. If you want the dye color to stay, it won't, if you don't it will. Tomatoes suffer from the same phenomenom, as does catsup and mustard.
On my website I have charts of colors you can expect, lightfast and washfast charts, scourning instructions, etc. Check it out at: http://www.prairiefibers.com I will be teaching at the Iowa Wool and Sheep Festival, in June, in Adel, Iowa if your interested in learning more.