Since the photo you posted came from a university website that explained what these galls were, did you not do any further research? The recommendation is to prune off and destroy affected branches and to disinfect your pruners between cuts.

Unless the plant is riddled with the galls, I doubt you need to be quite so severe as to cut it back to the ground. And since the cause of the galls has not been fully determined, it may or may not show up again.

This is the snarkiest, least helpful site.

Obviously I did read up on the subject to even know what they were and decided to use one of the nice clear photos of the problem found while doing so. I just wanted an actually helpful person to share their results if they had dealt with the problem in this manner as this is the best solution for my problem based on my situation and did not feel it necessary to dump all issues surrounding my particular situation.

For the record the plant is riddled from top to bottom because of an unfortunately timed hard trim last year. It rained almost every day for almost two weeks after, allowing the gall fungus to take hold.

The bush has a lot of dead branches and looks sickly. It bloomed almost 3 weeks after all other forsythias nearby. It usually is the first.

The bush was planted by a previous homeowner for a utility box screen. So, if possible I would rather try to save the bush than digging around in that area. But, not knowing how a bush in this condition would regrow, I posted here for advice. Big mistake, there.

Good bye from zone 7b.