If you are talking about 'Cupressina' Norway spruce then yes that skinny planting strip is not nearly big enough. If instead of lining sentinels up immediately in front of the fence you do a mixed planting of various shrubs over a much larger part of the space between the fence and the walk that will work out a lot better.

Where are you, Heidi? If in the humid Midwest, blue spruce (Picea pungens) are quite often spoiled by needle cast diseases. I don’t have plant suggestions for you, but others may if you provide general location so they know climate conditions for you (zone is not enough.)

We are in Montana. I have regular sized Colorado blue spruces next on the outside of the fence to block a commercial building. The now wide open area we are trying to block is another commercial built and a very busy road. Looking for something at least 12 feet tall. Our Brandon Arborvitaes were about 10 feet tall and did ok. But we had so much for back on them the last couple years and then many just died after a crazy spring and winter cold winter the last 2 years.

Large spruce on outside of fence. There is an alley on the side of the bare fence so we cannot plant there.

Blue spruce is prb'ly not affected by needlecast in Montana (being close to its natural range), tho those would overwhelm that fence in time. Toto too (in Witch of the North voice).

Arborvitae got rocked here in Wyoming the past couple years. MT gets the same WILD fluctuations in temp as WY. Solar minimums amplify that. I've given up completely on arborvitae. I've had way too many die on me. I'd suggest some kind of juniper. Woodward is one that was developed in Cheyenne, WY and seems to be hardy here in Laramie, WY. I imagine it would do well anywhere in MT

Same here. The nursery here said he can’t recommend Arborvitaes any more either. They are dead all over town. Thank you. We were leaning towards the Skyrocket or Taylor juniper or the Blue totem spruce. Our spruce trees are doing amazing here

If you go with Rocky Mountain juniper cultivars like 'Skyrocket' then these will be regionally adapted. Same as with Colorado spruce.

I have a Skyrocket here at my office. It is doing well and has survived these past couple, very trying, years. Very handsome tree/shrub. Very unique shade of green.

Virtually all of my evergreen trees had stunted growth last year. The culprit was an historic cold spell in mid April. Hoping for better results this year.

Blue spruce is virtually indestructible anywhere in the Rocky Mountain west (if given enough water). It's my favorite tree.

I planted an 'Iseli fastigae' blue spruce last spring and it appears to be doing just fine. Blue Totem looks neat. I was not aware of that cultivar

One of those last two is said to have a problem with losing the shape, I don't remember which for sure but it think it is the 'Totem'. And would definitely look into this before planting a whole hedge of them.

Just kidding. It's a Moonglow juniper at my office.

L Clark. I looked into the Islei spruce as well. There are some sites that say only 4 foot wide but many say up to 10-12. The totem is said to be more narrow. I love them to as they are what are doing well after the last crazy springs and winters we have had here in Montana. I lost a purple ash tree, I will be pulling out a total of 16 Brandin Arborvitaes and many shrubs and flowers—ones to at are rated for a zone 3. All around town they are pulling out dead trees. The Arborvitaes and ash trees did the worst. If I could build a 15 foot wall I would after what it’s going to cost to replace these trees and the time it took for them to get big.

Crazy . Same here. We don’t have many arborvitae here, but every single one is toast. We do have a fair amount of ash and I’d say 50% mortality with thos. big trees, too. also, any newly planted tree didn’t make it or had severe die back. It’s been a terrible couple years

There are some sites that say only 4 foot wide but many say up to 10-12. The totem is said to be more narrow

Neither remains columnar:

iseli fastigiate - Bing images

blue totem spruce - Bing images

What about Taylor Juniper for Montana?

We have a few of those in our yard but the snow has made a few of their branches arch out. The only way I can make them look good is to tie it up now or I will have a hole. But they are a nice dark green