Cheating to Win: Fences

There is an old saying “Good fences make good neighbours”. Except it isn’t really that old, a mere century or so. Universal fencing of properties is a relatively recent phenomenon in history. Before the industrial revolution made iron cheap building fences out of locally abundant stone or timber was a time consuming and expensive process. In many places those resources weren’t available so instead livestock were allowed to roam freely. The whole culture of fencing we are used to today was flipped on its head. If you wanted to have a livestock free space it was your responsibility to fence wandering animals out, unlike today where anyone who owns animals is expected to fence them in. Most places in history followed this pattern, with cropping fields, gardens and house yards fenced to keep roaming livestock out and a considerable portion of the land around a settlement grazed as a commons. The mass production of cheap barbed wire fencing in the late 1800s radically changed how people viewed ownership of livestock and land. The spread of the personal car was the final straw, with people unwilling to slow down to allow for wandering livestock. In many ways this fencing revolution greatly worsened the problems of mismanagement of livestock grazing since it made it easier to confine animals in spaces that were unable to support them. The dynamic and responsive grazing systems pioneered by workers like Alan Savory have showed that larger and more diverse flocks of herbivores constantly moving over larger tracts of land produce healthier ecosystems and animals. Where resources allow this can be emulated by investing in even more fencing to control grazing, though the opposite approach of combining herds and lands is showing similar success in less affluent parts of the world.

Beyond metal fencing high technology has gifted us electric fencing, which started to become widespread in the 1950s. This approach greatly reduces the amount of material needed in the fence compared to metal fences, with a single strand often sufficing for control of cattle. The efficiency is balanced though by increasing complexity since electric fences depend on reliable electricity supply, complicated integrated circuits to control the pulses, plastic insulators, and sophisticated plastic/metal lines. These materials in turn depend on long and fragile supply lines that stretch across the planet. Electric fences are also more fragile systems to operate, with a single worn out insulator, broken line or malfunctioning energiser rendering the whole system non-functional in an instant. I currently rely on electric fencing lines to control my goat herds, plus metal mesh for my poultry and the barbed wire boundary fences that came with the property to keep my neighbours cattle out. I often wonder how these various systems will hold up in our uncertain future, especially the dependency on high tech replacement parts for the electric fence system in the event of a breakdown in the global trade networks. These thoughts have encouraged me to experiment with alternatives that are even older, the use of living fences to help manage animal movement.

Most of us are vaguely aware of the European tradition of growing hedge rows as a form of living fence. These are composed of a diverse mix of species that often grow into small trees, meaning they need to be layed periodically, a highly skilled job where the branches are partially cut through, so they can be bent over and woven together, allowing them to regrow into a dense tangle. These hedgerows serve a much wider variety of roles than simply controlling livestock movement. Their bulk means they are effective wind breaks, unlike wire or electric fences. They often produce useful products such as firewood and seasonal food. Finally they are often a crucial habitat for wild life, which can have beneficial effects on the wider farm ecosystem. In our subtropical zone there is a much wider range of potential hedging species to explore, and in the tropics there is a long tradition of using various plant species to make living fences. A desirable hedging species needs to meet a long list of requirements and few species can do all at once. Different species have different capacity to contain different animal species as well. A good hedging species needs to be easy to propagate and establish, fast to establish, ideally only grow to the desired height so maintenance is minimal, and produce a dense and animal resistant growth form. Other desirable traits include the ability to produce some useful product, and wildlife support potential. I will outline how the various species I have trialled have measured up.

Mexican sunflower (Tithonia diversifolia) was one of the first hedging plants that I experimented with. It got out to an early lead since it is very easy to propagate, with unrooted cuttings sunk directly into the ground in autumn giving very high strike rates. A single mature bush will produce about one hundred such cuttings, and they can grow to their full height of 2 m in a single year. Like is usually the case fast growth comes at the price of flimsy wood. On the upside this makes cutting them back easy since even old stems are quite soft, but it means that animals like goats can push through dense clumps and snap branches. Goats don’t kill the shrubs when they graze them directly, but they do tend to beat them up a fair bit. The density of the growth is quite low underneath the bushes so poultry can move through them easily. The geese also strip the bark when confined in night pens surrounded by Tithonia, which doesn’t kill them but sets them back a bit. All of these factors together mean that Tithonia is not really suited as a hedging species, but it can be very useful as a fast growing nurse species as other better species that grow more slowly establish very well through Tithonia. Such quick hedges are very effective when combined with electric fences. Larger animals can often gradually push their way through even a fairly dense hedge given time and motivation. The can also often run under or jump over a single electric line if they are brave and quick. When you run a single electric line on the inside of even a flimsy hedge they synergise so the animals cannot move quickly enough to get past the electric fence in time. The visual barrier of even a flimsy hedge can also be an effective psychological barrier since many animals will be reluctant to go places that cannot see first. The grass is not greener on the other side if you cannot see it.

More promising is Malvaviscus arboreus (sometimes called turkcap), a Hibiscus relative that grows into a tangled shrub up to 3 m tall. They are covered in nodding red flowers which produce ample nectar for small birds, and host significant grasshopper and caterpillar populations for insect eaters. There is a form with crisp edible fruit as well that I am currently trialling that should be somewhat like a rosella, and the flowers are also somewhat edible. I have planted a dense hedge of this on the outer edge of my goat paddocks and I have been very impressed with its performance. It is a bit slower to establish, with my original plants grown from cuttings that were rooted in the greenhouse. I have since found that unrooted cuttings will establish reliably when planted underneath established Tithonia hedges during wet weather. This species is also browsed by the goats, but they usually leave the bark alone so it recovers quickly. The branches are very elastic and grow at all sorts of odd angles, forming a dense network. I suspect once fully established with sufficiently close spacing this species will hold back grazing goats even without an electric line. Taller plants like Leucaena seed nicely through the stands, adding extra density and higher quality fodder which can be pruned out and tossed to the goats. I suspect vines like muscadine grape and brambles like Atherton raspberry would also establish nicely through the tangle and increase its effectiveness while also producing a useful amount of fruit and more diverse goat forage. I suspect such hedgerows will still benefit from having a human present to graze with the herd, ready to provide a sharp whack with a long stick if they start exploring the depths of the hedge and risk breaking through. My herd requires about 90 minutes to graze twice a day. Traditionally this job would be given to older children. In a world without electric fencing this pleasant job might return.

An even slower but stronger hedging species is Calliandra haematocephala. This large shrub can grow to 4 m tall and produces pink pom-pom flowers that supply ample nectar for birds. If kept pruned it is capable of forming dense stands of thin stems, meaning that goats grazing the outer layers are unable to access the interior of the plant. The plants under my conditions are very slow to establish, but the dense older wood has the same thermal density as black coal so it makes excellent fuel for rocket stoves. They can be propagated by cuttings, but if you are observant you can collect seed before the pods shatter, making mass propagation easier and giving plants with stronger root systems. I suspect with soil that has a more typical mineral balance they would grow a bit faster. I have seedlings that are five years old that are about 1-2 m tall at most, consisting of a single flimsy stem or five. They will take a decade more at least at this rate to fill out. That said the immature plants are very tolerant of other species growing over them. I think for me the ideal progression is Tithonia to begin, with alternative Malvaviscus and Calliandra planted under them, with randomly sowed Leucaena and vines throughout. This type of hedge should be able to withstand limited direct goat grazing within a decade or two, during which time it will greatly enhance the function of electric fencing while also producing much needed fodder during droughts (a time when I typically cut back Tithonia and throw over the electric line to the goats).

All of these hedging species have the benefit and problem of being potential fodder species that need protecting when they are young, and being unable to withstand a really determined goat with a lot of time on its hooves. To fill this final gap in my living goat hedge roster I am hopeful that Aloe arborescens will fit the bill. This shrubby Aloe comes from east Africa, with a very similar climate to ours. They grow commonly in abandoned gardens here, and are found as remnant living fences around abandoned homesteads in Africa. They grow readily from small cuttings planted directly, but take about 5 years to fill out. This also means the generation time for one plant getting big enough to propagate again is quite long, though growing from seed might be a way to speed up mass propagation but would require two distinct clones to cross. They are spiny and bitter enough to deter goats, and have a dense growth form that extends to the ground, but are not so spiny as to be unmanageable. They also produce large spikes of nectar filled flowers in winter and have some minor herbal uses. The surplus biomass from the hedges can be somewhat problematic since it is succulent enough to not die readily when pruned, so it can regrow if left on the ground. If pruning material is piled up most of it dies in time and the few survivors can be dealt with before they establish. This species is likely to be gradually established around my external boundaries, in anticipation of a time when I may not be able to replace the crumbling barbed wire structures. Or maybe in that case a return to a culture of wandering livestock and fenced gardens will return and I can just use it to protect my cropping areas.

Finally it is worth mentioning the very different requirements for fencing poultry. I am currently about to repurpose a large amount of 90 cm high chicken mesh to seal off my orchard to contain my poultry there. The geese also go into night pens that are part of the vegetable garden rotation. From my trials there I have found that not many species have the required density close to ground level combined with goose resistance. Chickens are even better at squeezing through low gaps. Lemon grass is a bit too short and is grazed down by the geese, and tends to die out in winter. Vetiver grass looks like being the best option since geese barely touch it, and it is dense enough right to the ground provided it is planted closely enough, ideally in two rows that are slightly offset from each other. This species also produces useful mulch for the garden and bedding for the goats and geese. Its main downside is that it is a bit slow to propagate up to large numbers (the price paid for it being a well behaved sterile clone), and dividing clumps and establishing them is a little demanding, working best during the hot and wet time of the year (usually when other jobs take precedence). Vetiver has a very vertical root system meaning minimal competition with crops growing nearby. For the goose night pens I believe I will need to rely on a built structure to achieve the security I need with valuable crops nearby. My favourite approach is what I call a trash fence. Short upright bamboo poles are driven into the ground about 15 cm apart, spaced every 1-2 m along the fence. This creates a support system where all manner of flimsy branches can be pushed between the uprights, especially the twiggy upper sections of bamboo. I like this system because it reuses waste branches from feeding the goats, and it can be repaired on the fly. If an upright fails another can be put in its place. If the twiggy matter slowly compacts and decay more can be piled on top.

Zero input agriculture is like a game of Jenga where one support after another is removed, though our game differs in that we have the opportunity to put blocks back to fill in gaps and keep the structure standing. Like the ship of Theseus eventually none of the industrial components will remain. Fencing is one of these key elements and establishing post-industrial alternatives will take about a generation at least. Best get cracking and start your own experiments with hedges and living fences.

A mature Aloe arborescens. This uncommon form is more upright than the one I usually see.

A recently pruned Malvaviscus, showing the tangle of branches in its core.

Tithonia hedge showing extensive goose damage in a vegetable bed/night pen. These will be replaced with vetiver soon.

A double fence of vetiver grass (left) and lemon grass (right) in a vegetable bed. Often mixing species produces a better result.

A more mature vetiver hedge where the crowns have formed a solid wall, bounded by an electric tape line.

A mature Malvaviscus hedge and electric line, with a self sown Leucaena podding up.