I have the exact opposite problem, the raspberries are taking over. If your raspberry patch is in a sunny spot and somewhat dry soil, I think it'll take control on it's own. I think you have to kill sumac at the source or it keeps growing.

the raspberries were there first. and it is sunny and well drained. but the sumac is so aggressive and fast growing and it creates shade.

kill it at the source? what is the source? and, that sounds like an herbicide issue to me. i think the herbicide would kill the raspberries too.

you know, at least with the raspberry canes, you can mow them. that's sort of how i keep the raspberries from taking over. i think i really need to get in there in the early spring and do some serious pruning and cultivating.

When you say sumac, are you talking about a "choke weed" type of vine? If so, it grows through my raspberries and when it spreads out I have to follow it to it's source and pull it up. I may be thinking of something different.

here's a picture. it gets 15 feet tall. staghorn sumac. has red leaves in the fall. funky red flowers. i think you will know it.

Yes, I know it well. I hate to say it, but I cut the raspberry to let the sumac grow!

i wish i could let the 2 co-exist but both spread by their root systems and i am having trouble containing the sumac. as we know. it is getting the better of the berries. i can hang my bird feeder in the sumac, but we really like having those raspberries in july! we had very few berries this summer, and i dont know if that was just a normal thing--an off year--or if the shade of the sumac affected the canes. actually, now that i think of it, there were very few flowers. maybe the canes are taking a rest. gives me time to get them in shape next march!

did you plant your raspberries or were they already there?

They're wild raspberries with blackberries mixed in. There seem to be fewer raspberries this year, but plenty of blackberries and blueberries. Maybe it just isn't a good year for them. It seems the more you cut raspberries, the more productive the plants become. The bushes I plow snow into seem to grow the best.