I sure as heck wouldn't invest in sod until I figured out what the problem was! Moles excavate largish tunnels while voles are often seen above ground. Have you had any other plant damage other than the grass? Grass, by the way, can be killed by being exposed to the air in the mole's tunnels. So, just how ' little' are these hills, air holes, and tunnels? You are describing mole crickets to a T, you know. Size matters. Mole crickets are causing plenty of problems at this time of year. Just check out some of the other posts in this very forum.

They can be a terror! You didn't mention if you have small children or pets..but if you don't, there are commercial poisons sold..the most effective I've found is peanut butter flavored bait blocks. Just put a chunk near the hole..They will also attract squirrels, dogs, maybe even cats..so think about it before you just throw that stuff everywhere. In my case, I buried a glass jar with the bait inside, with a hole in the lid just big enough for them to get in..(those long skinny green olive jars are perfect!)bury it in their tunnel, or at least where they've been digging..then place a stick in the ground so you remember where it was..wait a few days, clear off dirt, see if bait is gone..if it is, add more bait..keep doing this until they're not coming anymore. You may have to place several in several areas if you're that over run with them..If you live in an area where the homes are close, ask your neighbors if they have problems, too..but be careful..you can quickly make an enemy by mentioning that you're going to put poison out.. at any rate, keep at it, then after that it's just keeping an eye out and jumping right on it if you see a sign again. Those chunks of bait blocks last a long time..it only takes a little to kill a mole or vole...you don't have to put out huge chunks all at once.

Although we are unable to see the end of the driveway where these would be placed, they could work. But I might have some concerns as to how appropriate a matching, paired planting might be for this purpose - that tends to be more appropriate for a more formalized setting - and there is also the issue of these solid evergreen pillars blocking the line of sight when backing out of the driveway........ Having said that, Emerald Green arbs ('Smaragd') are probably the most widely sold and planted tree in the US!! They are most often used for a narrow growing privacy screen, as illustrated by the photo, but individual plantings to provide a vertical accent are also common. But they are tough, hardy plants (although deer adore them) and will grow just about anywhere if given the proper care.

I love walls of emerald green arborvitae, especially their texture, color, and fullness/density. Here is a pic I took about an hour ago at Muirfield golf course(Memorial tournament). Love the wider spacing, this is gonna be a killer wall in 10+ years(road is to left of bike path, need to focus on putt). Looks like they disregarded the internet, which generally suggests 2’-3’ spacing for wall, when deciding on spacing(check out the dead one). If Jack Nicklaus approves Thuja Occidentalis Smaragd as a privacy screen, then they must be good lol. Id say 21, 5-6 footers for 850 is a good deal. Still small enough to “become one with the ground/established” rather quickly. Even the 10+ footer I planted 5 years ago did good, though the smaller the tree, the quicker they get established. I have seen tiny tots outgrow larger trees on more than one occasion. I didnt believe what people were telling me until I witnessed it. All the $5, 1.5-2 foot Smaragd I planted 4-5 years ago are gettin close to 5’, some might be more. In looking at the pic, and knowing that there are lots of deer here, (some of) these may be getting deer pruned, though just a bit. The right two perhaps.