Something balanced like a 10-10-10, 12-12-12, whatever, should serve the basic needs of both. That's why they call it "all purpose."

If you wanted to get more specialized, rhubarb, because it's essentially a "green" likes a high nitrogen fertilizer. Raspberries like something with higher P and K as compared to N.

But, "all purpose" is just fine.

Dave:

One of the very best fertilizers for both rhubarb and raspberries is hog manure. Are there any hogs in Iowa? Just kidding, I am from Iowa and I know there are some there. Maybe not quick and easy, but better than any chemical fertilizer you could find. Should be applied around the surface in fall and winter.

Don Yellman, Great Falls, VA

Ok Don, you're kinda starting to scare me with the poo. And yeah, there might be a hog or two around the State. I'll have to ask me uncle about that. . . . .might just go out and pull up a bucket of slurry from the sow house. Otherwise, ten bucks at Lowes for some nice, dry, odorless, chemicals are gonna happen. Bet it's the latter.

thanks tho, that's good to know.

d