This is an easy way to get BlackBerry stains out of clothes! I found this online:
1/4 C White vinegar
1/4 C cool water
1/2 tsp liquid laundry detergent
Mix and saturate the stain and if possible let’s soak for several hours/overnight
If the detergent solidifies in the solution just scoop it out and wipe on the stain. I had a nasty fresh blackberry stain on a pajama top and it was completely clean the next morning!