No, you can't split most shrubs like you can with a perennial. They usually come from a single growth point or stem/trunk and splitting that will just kill the plant. You will need to replace.....or if patient, the chopped off one could very likely regrow from that point. But it won't be fast and won't look very good for a couple of seasons.

That must have been some big mower to do that much damage to an established holly!!

It is one of those zero turn mowers. The first image is remaining holly bush.

I have a large Chinese Peony bush that is between my two holly bushes.

I don’t believe you can :( that holly bush might come back next year, just trim it better so it doesn’t get some disease for the cuts from the mower.

Have your son replace the holly he destroyed and perhaps he'll be more careful in the future.

not many trees or shrubs die.. simply due to pruning .. no matter how the pruning is accomplished ... or how badly it was done ...

and mostly that is becasue there is no impact on the established root mass ...

this is why i call many of them ... 'run them over with the truck' type plants ... i simply never considered using a lawnmower ... lol ..

i would also clean up all the rough cuts.. and just ignore it ... [if you can] ... and you might be surprised what it might look like by fall ... yes.. think in tree time.. rather than running out there every day.. and fixating on it ...

ken

Thanks so much; I am feeling a little bit better and maybe even looking forward to fall.

And don't use much fertilizer, especially later on this summer. Avoid slow release fert that will be feeding the plant long into the season, causing the plant to not harden off properly, leaving the possibility of winter kill. A little soluble fert won't hurt but nothing after June, just water properly.

What do I do as far as cutting back with the stems that are split to ground level?

Cut them off as close to the ground as you can.

OMG! I think I'd kill him. I once had a guy do my lawn and one of the shrubs I just planted started to look really bad a few days after he left. On closer inspection I found that he cut the shrub off at ground level with the weedwhacker and just stuck it right back in the ground to hide the fact from me. Grrrrrr! I was so mad! That shrub was a goner because it didn't have time to establish, but like everyone here said, most established shrubs are pretty indestructible because they had years to develop a good root system. Just clean up the cuts on a slight angle, put a nice layer of cow manure around the base, some good fertilizer with a high phosphate level (rock phosphate or super phosphate would be even better) and use a good bark mulch. If you want, you can plant something around it or put pots around it, or put ornaments around it to camouflage the fact that it was butchered, but don't shade it out. Eventually, it will look like the other one. I cut a dogwood shrub down to a few inches last year because it had gotten so scraggly it was an eyesore. Doing that is called scaffolding. I did everything I told you to do and this year it is coming back beautifully, nice and full, and developing that wonderful candle flame shape it's supposed to have. I wish I did it earlier. I also did that to Smoke Bushes, Forsythias, and mock oranges, and they are all nice and full now. So don't despair. Oh, and now that you can fully see around the plant, get those weeds out of there.

I tend to do things backwards. We have five blue spruce trees, a couple
groves of trees, a hedgerow, and a clearing about half a mile from the
house (our daughter's ashes are buried there)that I weed wack every
spring. I never get tired weed wacking but I am finding it harder to get
under my shrubs. I had just cleaned around a shrub on the side of my
house when this happened. Actually, I was thinking about having a
landscaper come in and mulch around the front of the house this year.
Decided against it, just won't be as fussy as in past years; but, it
will be presentable I think. My husband will be 94 in October and there
is nothing he can't do while he is on the tractor!

Oh, forgot...Thanks to you guys--I am beginning to find some humor in this!

I am beginning to find some humor in this!

==>>> good.. lifes too short ... ken

I'm back and yet another question...there are little shoots sprouting anything but holly leaves (red arrow) and what appears to be holly leaves (blue arrow)
are sprouting out of the larger roots. My question: What do I do with the suckers; cut them off at ground level?

Holly is very resilient. I had an ilex aquifolium blown over by a hurricane (yes we had one, a total freak). The garden wall down went with it. It was out of the ground for about three months, admittedly in winter so kept damp and cool. Once replanted off it went again.

Do you want a Holly tree or a shrub? If a shrub leave the shoots.

Here is what it looked like in 2010. It was much larger before being mowed over this year. This is one of two in the front of our house. I am hoping it will come back just as beautiful as it was before being hacked. Will it be enough just cutting the shoot to ground level?

"there are little shoots sprouting anything but holly leaves (red arrow) "

Pull the weeds and make sure to get the roots.