Inpenetrable living fence??

Ok, I want your suggestions....

I have about 1000' which I am looking to build an impenetrable hedge. The outside of the hedge will run along a wildlife corridor and irrigation ditch, and the interior side will be the border to our zones 1&2 as well as place for small children and dogs to wander.

I am thinking of building my hedge with ~3 types of thorny trees / shrubs. The outside layer could offer wildlife grazing, while the rest could be pollinator attractants, bird habitat and or berry producers.

I was originally thinking: Washington Hawthorne, thorny locust, Osage orange... All of which I would prune to a out 7' tall.

I am in a zone 5b in sw Montana. Your ideas for alternatives and why is much appreciated.

Thanks.

Do some research on hedge-laying. It's more than just cutting the stuff back to the desired height. You want to cut halfway through a lot of the stems right near ground level and bend them, so it sort of half-splits and half bends down, then you tuck it into the mess behind it, so it stays down. This part goes on living and growing slowly, and meanwhile more sprouts come up from below the cut. I think this process is repeated with new shoots every several years, and it's more important than simply shearing the outer parts and top, because it maintains high stem density near the ground where critters are likely to try to slip through. And of course if dead brush accumulates, vines and brambles grow up in it, it's all good....what you're after is a barrier to animals.
In the initial stages, some kind of physical fence or electric fence might be a good idea until the hedge gets' established enough to take some browsing and abuse.

Tim,
I'm on the drier side of the mountains here but I'm trying rugosa rose in combination with caragana planted at three foot centers. Caragana to the outside and the rose in a second row/layer on the inner perimeter. Rugosa rose produces edible fruits (hips) that have several uses and are certainly pollinator friendly. They are extremely thorny and are supposed to hit about six feet tall and about as wide.

I'm also trying sea buckthorn planted tightly. It too will have rugosa rose "backup" and then two rows of raspberries. Don't have too many deer out my way north of town but they do come by for a taste test now and then.

One other plant you might consider is buffalo berry (Shephardia argenta). It's native to the west and is tough, a nitrogen fixer, and produces berries edible to us and wildlife. It's somewhat thorny (related to Russian olive) and quite tough. I see a lot of it in the coulees/draws between the Wyoming border and Billings. I also see it in groves and mixtures in the Missouri River valley around Townsend so it is pretty widespread. I saw it in some pretty dry, alkaline spots in Wyoming and Nevada when I worked there.

My limited experience with honey locust (your thorny locust?) is that it wants to be a tree and keeping it so heavily trimmed may lead to undesired results or weak growth. Most of the thorns are on the trunk.The thorns are wicked- like four to six inches long.

You might look into a variety of Osage orange that was rescued from the old USDA Cheyenne Experiment station by folks at the Cheyenne Botanic Gardens ( sorry but the name escapes me at the moment). I think that High Country Gardens out of Santa Fe, NM sells this variety. Might be other sources out of Colorado. I suggest this one as it survived roughly forty years with absolutely NO irrigation on the extremely dry, windy plains east of the Rockies, north of Cheyenne.To survive forty years of land hurricanes that are commonplace in that part of Wyoming it is one TOUGH plant, for sure. You might want to check with Lawyer Nursery over in Plains, MT as they sell in bulk and you would surely need a lot to cover your 1000 feet. I have no monetary interest in either supplier but have done business with both and their stock is very healthy.

Good luck getting this established.

We're working on the same idea, using Osage Orange (called "hedge" for a good reason) along with fruit-bearing bushes on the inside of the thorny hedge. This is to create not only an impenetrable barrier on the outside, but to provide a useful interior crop. Hedge (Osage Orange) a very dense hard wood that burns at a high BTU. We use even the smallest branches for a raging fire in the woodstoves (perfect for cookstoves). It has a tenacious growth habit, causing it to send out multiple thorny branches for each one pruned away. Thus, by planting a small sapling in spring, cutting it down to one inch high that fall, the second year a thorny small hedge is begun. The second fall cut the new growths back to 1-2 inches long. Continue this pattern for 3-4 years. It is worth it as the final hedge is "bull-strong, horse-high and hog-tight" (hedge's claim to fame). We have been doing this during the past three years (two were major droughts). We made the mistake (i.e.- experiment failure) of planting them in small hay bales and too far apart (8-12 inches is the correcxt spacing- we did 24 inches). The droughts dried up the bales (on top of sod), causing some loss. However, the living hedges are mean-looking and treacherous, pointing thorny branches in all directions. These trees grow very quickly.
Last year, we saved hedge seed and plan to replace the empty spots and extend the border further.
I hope this helps. Please google more about this. There are magazine articles from ranchers' experience with growing hedge in the 1800s a predator/cattle/people-proof borders in the Midwest.

If osage grows in your climate, use it.

There is one British guy that has some interesting ideas on what to do. Part 1, Part 2 on construction, and Part 3 for managing the waste produced by a thicket hedgerow.