It shouldn't hurt it. IME, clems can take varying degrees of severe pruning and at various, less than desirable times and bounce back quite well. Depends on how well it is established and how extensive the root system is.

Forget using the root simulator. It is not intended for this sort of purpose and won't work the way you think it might. And depending on the product itself, may not be much more than snake oil :-) If you want to apply anything now, try alfalfa meal or alfalfa tea. It contains a natural plant growth hormone that encourages basal stemming, which will make for a fuller plant overall as well produce multiple stems that can guard against substantial damage from weed whackers or rabbits or even just breakage.

Other than the alfalfa, I woudn't do anything other than keep it well watered through the summer months. And maybe put a wire guard around it to avoid any further damage before it recovers fully :-)

thanks its Hermi-lome didn't give it much but have used it for years has a good mix for root stim. and not foliage low nitrogen , yeah a total oops stumbled and there you go , heck to get old.

Thanks for the help with that and the Big Guy on my side it may grow bigger than before.

It was a hard winter here lost several perinals or they were slow on emerging.

I take care of my church and cemetery plantings lost 6 Dense Yews lost 1 at my house that was over 65years old . oh well that's gardening

I second the alfalfa recommendation. The hormones do help more profuse stems.