Purple Gem requires almost full sun to do well. The photo with green growth only at the branch tips is pretty characteristic of plants growing in too much shade. Purple Gem also needs excellent drainage and is often troubled by lacebugs. Can't tell from the photo, but check the underside of the leaves for glossy brown specks of excrement - a sure sign of lacebug damage. All in all, though, I'd say moving the plants to a sunnier location is the best thing you can do.

Sun is not the issue because they get full sun for most of the day. That is why they are planted where they are because that is where they would get the most sun in my yard and the area drains well because the area slopes away from the plants. They have been doing well up until now and the only thing I can think of is the large amount of rain we have been getting lately. So if that's cause should I be pruning and fertilizing to help them come back stronger.

It's quite odd that the green growth is only at the branch tips in a full sun location. Recent heavy rain should not have been a factor either because the new growth was initiated right after bloom. A slope can certainly help with drainage but is not a guarantee. Even poor dainage, though, should not have caused the kind of growth seen in the photo. When the two plants were growing well, did they put out new growth from the base without the bare centers now seen? I'm also not sure if there are lots of completely bare branches or if they are mostly bare with green growth at the tips.

There isn't anything to do at this point in the year except to prune out dead branches if there are any. Pruning back toward the base right after bloom time next spring should cause new growth to break from that point. Fertilizer may help, but it's never a great idea to do it without a soil test first.

Are they planted too deep?
Just because the ground slopes away from them doesn't mean they're not drowning. They could be in a clay hole that retains water for too long a time. They should be in loose well drained soil with summer irrigation.
Pop one out of the ground and look at the rootball.
Mike