living fences /hedgerows

Does anyone have any experience with planting living fences? I am thinking about the formidable kind that would hold pigs and maybe a cow or two. Prickly Ash grows around my 10 acres like weeds and am constantly hacking it back from areas I don't want it. I think I could use some of that for the under story but I am looking for suggestions on what other species to use maybe as a dual purpose food forest row cropping system. The kind of hedge rows I had in mind were the kind the troops in world war 2 ran into when they broke out of Normandy. I was wondering to about the over story trees that could be planted close together without adverse effect. I should mention we are situated 60 Miles north of the Twin cities in Mn. cold zone 4 into zone 3 trying to find zone 3 fruit trees is a bit of a challenge. have been thinking about this for some time and any wisdom or practicle knowledge would be appreciated,Blessings Steve

Steven, I have many times in my childhood seen hedge apples (Maclura pomifera) also called Osage orange or Bois D'arc planted in thick rows along old fields and bordering properties (hence the name hedge apple). Nowadays people put up fencing, but in earlier times these gnarled trees were great for intertwining their branches to create a nearly impenetrable hedge. Even when the trees died the fence remained because the wood is so naturally rot-resistant that it lasts practically forever.

I think you can buy saplings or, if not, someone may have a tree or two they could get seeds from to trade with you because this tree has been naturalized throughout every one of the 48 contiguous states and even up in Canada. It's original range is Texas, but it is highly adaptable -- probably from having once actually covered (about 100,000 years ago) much of the range it is now naturalized in. I guess you could say it is native to all the U.S. and Canada, but merely temporarily extirpated from all but a tiny area in Texas. It's coming back into it's own, finally.

Anyway, it would make an excellent choice for what you have in mind because it is extremely hardy. The only thing is that the fruits (relatives of mulberries, by the way) aren't really edible even though they are not poisonous. The milky "latex" is just too disgusting and bitter. They make excellent missiles however. My brothers and I had a great time throwing them at one another when we were kids. They hurt a whole lot more than snowballs, I can tell you! If you can find a good use for them they may still be worth it for you. The wood is great for making bows, and if you have enough of them, you may be able to sell them to the folks manufacturing a very high-priced oil called Pomifera (@ $180 per/ton for the "apples"). That last is based on a discovery by a chemist in Iowa. Read here ... NPR: Iowa Chemist Turns Inedible Hedge Balls Into Valuable Cash Crop

I am no sure how well Hedge Apples grow here in MN. I have not seen many if any trees around (I am on the warmer side of Zone 4). I really would like it if they do grow here, because they sound like the ideal tree for hedgerows.

As to Zone 3 fruit trees try taking a look at St. Laurent Nursery in Potsdam NY (http://www.sln.potsdam.ny.us/) They grow their trees in Zone 3 so anything they grow should work for you as well.

Now as to Hedge rows. I would look more into Shrubs rather then trees. There are a number of thorny shrubs that can be grown in Zone 3 with some that produce edible berries. Everything from a Raspberry thicket to Seaberry (Sea Buckthorn). I am sure there are more shrubs that would work as well.

There is also a Tree Nursery north of Duluth, but I can't find that info right now.
I also see in my email history there were a bunch of tree pruning courses in the Duluth area which could also net you some more places to get trees and hedge row plants (Found through some UofM email lists - SUSTAG being a good one.

Bernard Welm wrote:I am no sure how well Hedge Apples grow here in MN. I have not seen many if any trees around (I am on the warmer side of Zone 4). I really would like it if they do grow here, because they sound like the ideal tree for hedgerows.

Bernard,
You should definitely try to get some seeds or saplings if you are interested in them. According to everything I have had read (and know personally) about them, I'm sure they would do well where you are. If they can grow them throughout most of Canada, they'll grow in MN.

I am also in Zone 3 and interested in living fences. I have never planted one myself, so I can't speak from personal experience. I've done a bit of research and seen what other people have done, but take the following with a grain of salt since I haven't done it myself.

American Plum (Prunus americana): In its northern range it is supposed to grow as a bushy shrub that can sucker and form thickets. It has a reputation for being thorny, but I think they aren't true thorns but rather sharp little branches. If it is the same variety that my grandmother talks about growing wild when she was a kid, then the fruit will be decent but so sweet you can make yourself sick and doesn't keep well. I know people grow this in Fairbanks, Alaska (Zone 2).

Siberian Pea Shrub (Caragana arborescens): A lot of people grow this in Fairbanks. It is on the list of plants to watch for potentially being invasive. It has thorns and fixes nitrogen. It makes a bunch of pea pods that aren't bad tasting when they are younger. A lot of people up there trim it into a decorative hedge. It's fun to listen to the popping noise when the pods start maturing and launching their seeds everywhere.

Sea Buckthorn (Hippophae rhamnoides): Another spiky, berry producing nitrogen fixer that is grown in the interior of Alaska. I've heard mixed reviews on the taste of its berries, but they're supposed to be very healthy to eat. Usually people juice them and add them to other types of juice.

Hazelnuts/Filberts: Nut producing shrubs. Not thorny, but my understanding is that they were frequently used to make living fences in Europe. Beaked hazelnut (Corylus cornuta) and American hazelnut (Corylus americana) are both native to the U.S. and supposed to be quite cold hardy. The hazelnut commonly grown for commercial production, Corylus avellana, is not as hardy. Badgersett Research Corp has been working on hybrids of the commercial European hazels and native filberts to produce cold hardy, disease resistant productive plants. According to their website they're definitely hardy to Zone 4 and probably to Zone 3.

Many plants in the genus Elaeagnus are thorny, nitrogen fixing shrubs that sometimes produce edible berries. I tried to grow Russian Olive in Zone 3 but I got poor germination and none of the plants survived the winter. That doesn't mean you wouldn't have more success. There are also a lot of other Elaeagnus plants to try out. I'm starting some Goumi seed this summer.

Dwarf Siberian Pine (Pinus pumila): A short, bushy pine that is supposed to be somewhat like Mugo Pine. It produces edible pine nuts. While the nuts are smaller than other pines grown for nut production, the tree stays short so harvest is much less daunting. My grandmother has some Mugo pines, and I think that they have the potential to be the best living hedge for keeping out moose. If this tree has a similar growth habit that would be awesome. People have planted them in Fairbanks and they are surviving but I don't know that any are old enough to start producing nuts yet.

Another productive evergreen that might make a good hedge is Juniper. I'm going to try a few, but I'm on the fence because a lot of the extreme cold tolerant ones I've seen are also fairly prostrate. If you're looking for a pig fence that might be fine, I'm more concerned with moose.

Cherry Prinsepia (Prinsepia sinensis): A thorny, berry producing shrub. I didn't have good germination and none survived the winter, but it still might be worth taking a look at.

Serviceberry (Amelanchier): My understanding is that commercial producers grow them as a hedge, but I'm not sure how good they really are for that. They are definitely tasty and cold hardy. There are a bunch of different types and they range from small bushes to small trees.

Roses: Planted thick enough some roses might make a good hedge, and rose hips and petals are edible.

Nanking Cherry (Prunus tomentosa): A fruit producing shrub that forms thickets. It is very cold hardy and sometimes planted as a windbreak, but I don't know if it would make a good hedge.

Like I said previously, I'm in Zone 3 and want to plant some living fences. I mostly concerned with moose, so I'm more interested in something fairly tall. Pigs don't need tall, but you would probably have to worry about them worming their way through along the base. As they grow, trees and bushes usually become more open at ground level. Traditionally hedges were often laid (lain?) by cutting the saplings part way through and then bending them over. Sometimes the ends were buried in the ground. This way the trunk becomes a horizontal crosspiece low to the ground to help keep animals in, and the branches start growing vertically. I haven't tried this myself, but it seems pretty interesting. I'm going to try it, but I think I'm also going to try to make my hedges very thick to deter animals from worming their way through.

You can actually use that method to train a lot of fruit trees to a hedge shape. There are plenty of apples and plums, and a few sour cherries and pears, that should grow in your climate. I'm hesitant to do this with anything grafted though, since it seems like it might just be a big vole feeder in our high-snow area.

I'm trying to start American plum, Nanking Cherry, Sea Buckthorn, serviceberries, hazelnuts, Dwarf Siberian pine, and Rosa rugosa from seed this year. I'm going to plant a bunch of them into an experimental hedgerow. It will of course be years before I'll be able to tell what seems to work and what doesn't. By that time I'll hopefully have the site for my large, Zone 3* food forest nailed down and cleared. I'd like encircle it with a large hedge maze, both to help keep moose out and convince people to come visit.
*In this case I'm talking about permaculture zones, not USDA hardiness zones, but I guess it works either way.

There are some mature Mugo pine and a mature Siberian pea shrub growing near where I live. I'll see if I can snap some pictures.

Deb Stephens wrote:

Bernard Welm wrote:I am no sure how well Hedge Apples grow here in MN. I have not seen many if any trees around (I am on the warmer side of Zone 4). I really would like it if they do grow here, because they sound like the ideal tree for hedgerows.

Bernard,
You should definitely try to get some seeds or saplings if you are interested in them. According to everything I have had read (and know personally) about them, I'm sure they would do well where you are. If they can grow them throughout most of Canada, they'll grow in MN.

From the research I have done it seems like Headge apples grow until zone 5. Can you point me to any research that says they will grow in cooler areas then that. I do want to start some trees and see what happens but it is lower on the list of priorities.

Hi Steve..... My Dad planted a rabbit/raccoon/deer/cow, proof hedge in Michigan... it grew about 6 feet high and over a few years spread about 5 ft wide... new plants coming up from the roots about every 3"-4"... it got very thick ... and is very thorny... it's common name is; Multifloral Rose .... and it makes rose hips

Looks like Osage Orange will grow darn far north, though it may not be native there: http://plants.usda.gov/core/profile?symbol=MAPO

Bernard, I can't find the URL of the article I saw saying that the original range (prior to the last ice age) was essentially all of North America, but this one shows part of the range -- including a big chunk of Canada and much of the northern U.S. USDA: OSAGE ORANGE Maclura pomifera At any rate, even if it does not show as naturalized in MN, it is perfectly capable of being grown there. The areas shown on the map in this .pdf are every bit as cold as where you are.

Deb, I bet this is the article: https://www.americanforests.org/magazine/article/trees-that-miss-the-mammoths/

That was a really interesting article! I heard that avocados had such big seeds and fruits because of megafauna, but I didn't realize there were so many plants in a similar situation.

Something to consider about those USDA maps showing where Osage Orange/Hedge Apple grows is that they tend not to be very granular. If something grows in one part of a state, the whole state is colored as it growing there. I've run into that problem with plants in Alaska. I'll get excited because Alaska appears to be one of the states where the plant grows according to the USDA map, but then it turns out it only grows in the extreme southeast part of the Alaska Panhandle, which is about 1500 miles away IIRC. Looking at the USDA maps linked a big part of the northern part of Osage Orange's range is Ontario. Ontario has a bit that extends down south past much of the northern U.S. (and is also nestled in between large bodies of water). It could be that it grows in this far southern part of the province, but not in the rest. If you look at the map it is not listed as growing in the majority of the more northern U.S. states, and none of the other Canadian provinces. I'm not saying that it can't be done, it's just something to be aware of.

Here's an interesting article on the fruit of Osage Orange having economic potential: Iowa Chemist Turns Inedible Hedge Balls into Valuable Cash Crop

I forgot to mention hawthorn (Crataegus) before. It's a genus of spiky shrubs that produce a fruit that is supposed to be tasty in jellies and a good medicinal.

Considering that the southern tip of Ontario is zone 6 it would definitely grow there.

From what I remember Osage orange grows to zone 5.

Tyler Ludens wrote:Deb, I bet this is the article: https://www.americanforests.org/magazine/article/trees-that-miss-the-mammoths/

That's it! Thanks for finding it. I found that incredibly enlightening when I first read it and always had it in the back of my mind for future reference. Then a couple of months ago when I heard the NPR broadcast about the guy making more money from his hedge apples than his corn crop (we both posted the same link on that -- great minds think alike ) I started seriously considering growing some here on our land. I've loved them since I was a kid (for dumb kid reasons), but now I have good grown-up reasons to include them on the homestead.

You mentioned that the USDA plant database lists an entire state if a plant is only found in one portion of it, but the reverse is true as well. If a plant has been known to grow in a state, but it has not been officially documented, the entire state is left out. There is a LOT of leeway on those maps in both direction from my experience. You probably already know this, but for those who don't -- you can click on the state on the large U.S. map and it will zero in on the state showing counties where the plant has been reported. You can also find out more about the individual genus/ species within a family by going to the classification tab too.

Edit: Forgot to say that the USDA map shows incidences of plants found already growing in the state. It does not mean a plant cannot be grown there. If the climate is right, you can grow whatever you want in your own yard, whether it shows up on a map or not. (Unless it's illegal, of course. )

One last thing, Tyler ... I noticed you mentioned a couple of Prunus species as living fence possibilities, which is great for a garden or field fence. However, if someone plans to keep livestock -- especially horses or goats -- inside a living fence, I would steer clear of any prunus species. The fresh leaves are usually okay, but dried leaves (from a fallen branch or from the autumn drop) can kill livestock if they eat them. The leaves contain cyanide, which is more concentrated as they dry.

Deb Stephens wrote:Then a couple of months ago when I heard the NPR broadcast about the guy making more money from his hedge apples than his corn crop (we both posted the same link on that -- great minds think alike ) I started seriously considering growing some here on our land.

Sorry, somehow I missed that you had already posted a link to that article.

Deb Stephens wrote:You mentioned that the USDA plant database lists an entire state if a plant is only found in one portion of it, but the reverse is true as well. If a plant has been known to grow in a state, but it has not been officially documented, the entire state is left out. There is a LOT of leeway on those maps in both direction from my experience. You probably already know this, but for those who don't -- you can click on the state on the large U.S. map and it will zero in on the state showing counties where the plant has been reported. You can also find out more about the individual genus/ species within a family by going to the classification tab too.

Edit: Forgot to say that the USDA map shows incidences of plants found already growing in the state. It does not mean a plant cannot be grown there. If the climate is right, you can grow whatever you want in your own yard, whether it shows up on a map or not. (Unless it's illegal, of course. )

I actually didn't know that it was possible to zoom in to counties on the USDA maps, thanks! That makes them way more useful.

You definitely make a good point about things being possible to grow even if they haven't been officially documented.

Deb Stephens wrote:One last thing, Tyler ... I noticed you mentioned a couple of Prunus species as living fence possibilities, which is great for a garden or field fence. However, if someone plans to keep livestock -- especially horses or goats -- inside a living fence, I would steer clear of any prunus species. The fresh leaves are usually okay, but dried leaves (from a fallen branch or from the autumn drop) can kill livestock if they eat them. The leaves contain cyanide, which is more concentrated as they dry.

That's another good point. I was reading about Mayday trees (part of the Prunus genus) killing moose in Anchorage, AK. The article said that when the trees are stressed, particularly after the first frost, they produce more cyanide so that at certain times of the year they are much more poisonous than others. People plant a lot of Mayday trees in Anchorage because moose tend not to eat them, but the article said that so many had been planted that the moose didn't have many other options. Most of the moose killed were juveniles, which would make sense because they have such a smaller mass, but even a juvenile moose is bigger than a goat.

I was reading a different a different article about moose browse preferences and Prunus species. If I remember correctly the article said that while moose have a preference for non-Prunus trees they will usually eat a little if it is around. Usually they don't eat enough to hurt them. The thing I thought was most interesting about the article is that pretty much all the trees moose browse on are poisonous to them, but they each produce a different kind of poison so moose evolved a behavior of eating a little bit of everything in order to keep from building up too much of any one poison.

I originally thought not to include any Prunus species in my hedgerows, because I don't want to accidentally kill any moose. I've since started to think that it probably would be okay to include them as long as they only make up a small part. I also think I'm going to make the outer part of the hedge out of evergreens.

We have some goats, but keeping them out of my fruit trees is going to be a priority. I was thinking I'd run some pigs and chickens in with the fruit trees, but I was going to use electric fence as the primary means to keep them contained. The hedge would be more to keep other things out and as a backup in case my electric fence fails to keep the pigs and chickens in. Do you think that would likely be a problem? I'm planting plum and cherry trees as part of the food forest, not just the hedge.

Thanks to all who posted you have been very helpful I have a lot to research and think on. Thanks

I forgot to mention hawthorn (Crataegus) before. It's a genus of spiky shrubs that produce a fruit...
Beware that hawthorn can turn your whole pasture into a thorny labrynth! It did this to a neighboring property on San Juan Island, WA (where many fields have hawthorn hedges) from bird-scattered seeds. Then it spread into our pasture after we stopped grazing and haying it. It would probably take a bulldozer now to clear it. But we sold the property, and now I'm trying vigorously to control the few hawthorns coming into our new pasture.

Steven,

Would love to be updated on how your living fence project goes. I have been contemplate living fence for several areas.  If grown from seed, it's by far the most economical option. And, depending upon the species selected for the fencing, the fencing can serve additional functions for the landscape.  

Like you, I have been strongly considering Osage Orange.  It was one of the many choices suggested in the Mother Earth article I read on the subject.  Siberian pea shrub, honey locust and black locust were also on the list.

Where I am, USDA zone is not so much a concern in my choices.  My soil may not be right for black locust. Gonna try anyway. It's a nitrogen fixer. Its nectar arguably produces the best honey, I hear.  Its wood is incredibly resistant to rot.  It coppices well.  The bark of green branches makes good fiber for weaving.

What the Mother Earth article suggests is using at least 2-3 species to make up the living fence.  And after going over the qualities of several particulars species, some of which, I've mentioned above, there's this almost throwaway paragraph at the end.  To wit:

For an inosculated fence, elm, a number of the oaks, olive, dogwood, beech, hornbeam, peach, almond, hazel (filbert), a number of the willows, sycamore, grape and wisteria. Trees with pliable branches are especially suitable, with apple, hawthorn, linden, and pear among the best.

Now, I keep having to look up "inosculate." I think it means "to fit close together by intertwining."

Anyway.  My thinking.  While Osage orange may not be hardy where you are, surely some cultivars of some of the other species on that list are.

But, apart from that, I just,think the idea of living fences is just wickedly cool.  My internet searches have turned up precious little in the way of examples.  Just a lot of instructions in how to do it.  Would love to share notes with someone constructing one now.  Particularly pics in progress.

When I get started I'll post my progress here

I am thinking this is the newest thread on the osage orange (whole or part).

In 2006, someone in Australia published an article on the osage orange hedge in Peats Crater, New South Wales, Australia.  I think that is probably the best source of information on Osage Orange I have seen.  US government articles on the silvoculture of osage orange would probably be next (although the Aussie paper contains a significant chunk of what I think is a silvoculture report from the USA).

At one time (when?), osage orange was known to winter kill in the NE corner of Colorado and in Iowa.  What killed a lot of osage orange in the Great Plains, was the two consecutive winters of 1855/56 and 1856/57.  I don't know how cold that was.

At least in some versions, the Great Plains osage orange hedge was 5 feet tall and 4 feet wide.  I suspect in most localities, osage orange is a desirable food for deer (moose, elk, ...) and in some localities it is the preferred food source.  A 5 foot tall osage hedge will be browsed/grazed all over by deer, moose, ....  Deer browse to about 7 foot height, and moose to 10 feet.

The generic description of the height of the hedge in Peats Crater is 3m.  Apparently there are osage orange trees making up hedge, which got to 10m.  There were osage orange planted away from the hedge, which grew taller than that.

The shade under the osage orange is dense enough, to stop encroachment of many species.  If you want to grow an osage orange hedge, you cannot let grass encroach on it.

Osage orange are known to grow in the company of honey locust.  This comment seems to have been in a forest setting, not a hedge setting..

The thorns form where the branches get lots of light.

An old osage orange hedge can be (partially) clear cut to obtain about 2500 fence posts per km of hedge.  You can let the suckers grow back, if you protect them from grazers (like deer).  The scrub from cutting the hedge works for this.  After a year or so, you want to thin to about 79 plants per 100 feet.  (that is a prescription, not my idea).

An old osage orange plant consisting of a single stem which is pruned, apparently is likely to die.  If it consists of many stems, you probably will be able to "revive" it by pruning.  The suggested pruning height is about 3m.

Up here, the information I read on deer, is that they can jump a 14 foot fence.  Will they jump over a 10 foot osage hedge?  My feeling, is that if the hedge is taller than 15 feet, they won't try.  And a hedge taller than 15 foot will not be browser to death by moose either.

Osage orange like water.  Once established, they will tolerate drought.  But they like significantly more water than I get on the eastern slopes of the Rockies.  If you want them to grow tall and fast, water and nitrogen seem to be needed.

---

For people to use osage orange as wood, it seems that there is a real incentive to get chunks of osage orange that are at least 10 feet long that are straight (and not twisted).  Apparently in nature, osage orange will grow to about 6 feet tall, and then all hell breaks out and it goes all over the place.  Can you get to 10 foot just by pruning?  Do you like dealing with thorns?  Apparently, people working with hedge (such as clear cutting it) go through two pairs of leather gloves per week.  The latex in the tree/fruit/leaves will also pretty much ruin clothes.  So, save one set of clothes for working with this plant.

Some people know of a "sun tunnel".  A skylight thing that is meant to "collect" light and deliver it inside.  There is a lot of reflections inside the collection tube, which pretty much destroys direction information for the light coming out of the sun tunnel inside the "house".  In the context of being able to grow osage orange straight, it was said you could do this in deep forest.  What I am thinking, is if you build a "building" where the ceiling of the building is at least 10 feet, and you have a sun tunnel above each osage orange plant, that approximates the deep forest.  I don't know if you would need curtains to shield light from other sun tunnels at tree N.  So you grow the tree until it is too big for growing in the building any more, and then you transplant the thing.  Perhaps by this time, it is ready to produce flowers, and so you can "sex" the  plant.  That may allow you to only plant male osage orange in a hedge.

Gordon Haverland wrote:

Up here, the information I read on deer, is that they can jump a 14 foot fence.  Will they jump over a 10 foot osage hedge?  My feeling, is that if the hedge is taller than 15 feet, they won't try.  And a hedge taller than 15 foot will not be browser to death by moose either.

Not sure about deer there, but people that make a living from their crops use 7 foot fences at the highest in this area.  I have never seen or heard of a whitetail jumping higher than that.  I have heard people say they can jump a 14ft or higher fence, but I personally don't believe it.  Deer also prefer not to jump over something if they can't see what they will land on, so a 6 ft hedge is better than an 8ft chainlink fence in my opinion.  I would think a good, thick hedge that is 6 or 7 feet tall would be plenty.  

I'm in zone 4b and just bought a pretty large new property.  I am planning to use osage orange, black locust, siberian pea shrub, and seaberry as the basis for my living hedge, along with other bushes and trees for small bird habitat, bee plants, and beauty.  I'm very hopeful that osage orange can survive here, but I'm not at all sure of that.

It may be mule deer that can jump the 14 foot fence.  I have both whitetail and mule in the area.

I also live about 5 miles downwind of a 100+MW wind farm.  So the osage orange hedge I am looking at, is the first row in a windbreak.  As I understand dense windbreaks extending to the ground abutting an "infinite" open space, is that the vertical deflection is about twice the windbreak height.  So a 6 foot hedge deflects winds to about 12 feet, a 20 foot hedge would deflect winds to about 40 foot.  A taller initial hedge will reduce the stress put on rows further downwind (if they extend above this double hedge height).

A horticulturist who is now retired (and has taken up woodturning) I met recently, was very interested to hear that I am thinking of growing osage orange.  She thinks they will grow here.  She would like to get some wood to turn at some point.

Here in the UK and Ireland we have very old Hawthorn hedges that will stop all people and livestock.
It is natural Barbed wire. I should know as I've just finished laying 165m of Hawthorn hedge.
Look up hedge laying for ideas as you could probably make Andy hedge stock prof this way.
I didn't lay the hedge the traditional way as its a very mature hedged that's been left unmanaged for years so I cut most of the branches off the uphill side then cut most of the way through the trunk and bent it uphill, so the hedge eventually looked like messy hair that had been combed up hill. Hawthorn is medicinal and makes a good tea and berries are enjoyable

Tyler Miller wrote:
Hazelnuts/Filberts: Nut producing shrubs. Not thorny, but my understanding is that they were frequently used to make living fences in Europe. Beaked hazelnut (Corylus cornuta) and American hazelnut (Corylus americana) are both native to the U.S. and supposed to be quite cold hardy. The hazelnut commonly grown for commercial production, Corylus avellana, is not as hardy. Badgersett Research Corp has been working on hybrids of the commercial European hazels and native filberts to produce cold hardy, disease resistant productive plants. According to their website they're definitely hardy to Zone 4 and probably to Zone 3.

I can personally vouch for these in zone 4b, and they are the most beautiful hazelnuts you ever saw.

I read an article some time ago about the making of bois d'arc hedges for fence.  
I cannot remember where i saw this, but the basics of it went:
settlers spreading out across the US would take with them bois d'arc saplings to plant when they arrived at their destinations.
the idea was that they would form a fence with bois d'arc grown very close together that they described as "bull tough and hog tight."
the process involved collecting bois d'arc fruit (we always called them horse apples)  fill a barrel mostly full with them so that they could be covered with water and allowed to stand then freeze and thaw a few times over the course of a winter.  in spring time, the barrel would be mashed and stirred into a slurry, releasing all of the seeds.  the resulting slurry would be poured into a shallow trench along where the fence line needed to be.  eventually the plants would grow into an interlocked, tangled thorny hedge.

having dealt with stubborn animals that refuse to recognize the authority of various regular fences, I have been wanting to give this a try.  just as soon as I can collect the fruits that I need before the squirrels get to them.