since its the front of the house... i would replace ...

looks like the standard emerald green.. more properly known as smargard ...

just buy whatever BBStore has in the size you want ... most peeps cant tell them apart in this category ...

if you cant find a match ... you buy two .. and move the odd one.. out back or some such ...

fall is the next best planting time .. in the midwest ... it is just going to be too hot in the next few weeks... if the rain ever stops ...

besides.. BBS usually get new stock in fall ...

if you are going to a good nursery... you can push those limits ...

try to find single leader plants ... better for snow load issues in the future ...

and before you do anything else ... speaking of snow ... if its a snowblower issue.. then maybe this isnt a great place for this kind of plant ... maybe it would be better to get rid of both of them.. and plant something that dies to the ground in fall ...

ken

Any deicing salt on the scene? Otherwise this kind of damage to conifers can in fact be winter injury. The part that is left looks fine except the original intact top was much bigger.

looks like the standard emerald green.

These do not have the density or spray structure of 'Smaragd'. You might have bought something like 'Techny' or 'Wareana' - but there is a large number of different kinds of Thuja occidentalis in cultivation. And you will need to find something on offer that is of matching size - if it also looks to be the same kind or similar that may be good enough, with learning exactly which particular kind you bought the first time perhaps not really being necessary - or feasible.

This situation exemplifies why it is preferable to avoid formal planting or other situations where if one of the specimens goes south it spoils the entire effect - formal planting should be limited to those instances where geometrically symmetric architecture calls for matching planting.

I also would replace it, but probably not with another arborvitae which are intolerant of salt. Since it's next to your drive, unless all the runoff drains away from that area salt will end up in the soil, either from direct salting of the drive or from salt dripping off cars parked in the drive. A short fence with perennials planted in front of it may work better in this situation to hide the trash cans, or perhaps you can do a web search for salt tolerant shrubs to plant there.

They don't look much like my Techys which are darker green, more dense, and fatter for the height.

The last photo looks like there are some holes in the mulch at the plant's base. If small burrowing rodents such as voles or chipmunks have been making tunnels down there, that also may have hurt your arborvitae.