Tuesday, March 27, 2018

The catch 22

What I'm about to write about our property, is a potentially controversial subject. It's a species of tree which showed up, on the edge of our front verge. Which is not uncommon, for this particular tree. As it has a weed status in Queensland, and is known for populating waterways and roadways.

Front slope

It went unnoticed for a while, but after conducting research into permaculture, support species trees, I discovered the tree growing near our front verge, was indeed, Leucaena leucocephala. It's appreciated in permaculture circles for it's nitrogen fixing qualities, quick growth and hardiness. Which makes it perfect for chop and drop material. It also doubles as fodder for ruminants.

Being listed as one of the most invasive species, in the world, it's therefore a controversial plant to have growing on one's property. I've been watching it's capacity to spread, and can vouch for said reputation. Yet, for our property at least, it's become a valuable resource too. Because it can live off our rainfall, without additional water, and provide an endless supply of carbon to utilise.

What's more, where the original tree grew, prevents soil erosion. THE number one reason, it was allowed to stay in place.

 16 December 2010
~ lead up to January floods, 2011

Run-off from our neighbour's driveway (see the top of the picture, above) crosses the street, in torrential downpours. It subsequently, runs down our front slope. The roots of the leucaena tree, however, helps keep the soil in place. The thicket of saplings which have sprung up, near the original tree (as a result) also act, to slow the flow of water, down the slope.

 New saplings emerging under older ones

Invasive? Yes. Absolutely But it's nonetheless, doing it's job, where no other native has managed to occupy that space, as well. We have acacias (black wattle) growing on the slope too, but they die quickly, and tend to get knocked over, after the wet and windy weather, arrives.

So as much as I'd love to support native species, they're not performing in that particular location, to prevent land from eroding downhill.

 Dying, black wattle ~ fell over in wind, 2016

Let's be clear, my job as land steward on slopes, is to keep my land in place. It's just as environmentally destructive, to ignore soil erosion, entering waterways. I'm in a catch 22 situation. Well, I would be, if I didn't have a third option.

If leucaena was to stay (as I decided they would) to benefit my land, I had to keep it's spread under control. I would be as industrious with this tree, as it was industrious, in it's production. Leucaena would deplete, before I ran out of uses!

 Cover the bare soil

The number one reason it's so useful, is for rapidly producing, chop and drop material. I use it to regularly mulch my fruit trees. The foliage is high in nitrogen, and the thicker branches, take several years to break down.

My mandarin tree (presently in fruit) got the royal treatment, recently too.

 Lovely, thick layer of mulch ~
produced from our landscape

It got a bunch of pulled grass, weeds and pumpkin vines, followed by the luecana foliage. Large branches first, followed by the finer, foliage on top.

This will serve a good year or two, but more than likely, I will add more mulch, when it's in plentiful supply.

 Same slope

Another use for the leucaena, is attempting to establish other natives on the same slope. Above, is a Grevillea She-oak sapling, and further back (barely noticeable) is a flowering ironbark.

Being a north-facing slope, it cops a lot of sun, all year round! Consequently, it has dry, depleted soils. The wattle branches I put around it several seasons ago, has since broken down - mostly. It was time for a new mulching treatment.

Support structure, in place

Only this time, I cut the leucaena into pegs, hammered them into the ground, and placed the rest of the branches and trunks, as a kind of retaining wall. It's all biodegradable, so designed to be absorbed into the soil, over time.

Yet it will adequately serve it's purpose, of retaining the rest of the mulch, laid on top...

Ready for another season, or two

As with the fruit trees, I like to lay the larger branches in contact with the soil, first, followed by the finer leafs and twigs, last of all. It shades the soil, retains moisture and helps this tree-grevillea, establish a little better.

My goal is to plant out the slope with non-invasive plants, to eventually make the leucaena redundant. For the moment however, it's hardiness and ability to produce carbon for our soils, on minimal rainfall, is imperative.

Trusty tools

The wood is very easy to work with, I only need a few manual tools: a large axe, a hatchet, pruning saw and hand pruners. The hatchet, aids in carving the pegs, to make them easier to hammer into the ground. The rest, help break-up the various thicknesses of branches and trunks.

Cut low to the ground

I am coppicing these, so they may well grow back with new foliage, to chop, at a later date. That's the goal of keeping them, anyway. To get as much free mulch as I can, to feed the plants I want to grow - eventually making leucaena, redundant. At least in this area.

If I get goats (on the wish list) I would deliberately cultivate these as food. The goal of course, is to continually harvest the foliage, so it doesn't get a chance to set seed.

Separated into branches, twigs and foliage

While leucaena may be a controversial tree species, I have to credit them for filling a gaping hole, on our property (literally) being the capacity to reduce soil erosion. I know there are those with an aversion to exotic plants, especially ones with a reputation for spreading. Normally, I would agree. On paper, I would agree.

Out here, in the field however, when choosing between watching your land roll down the hill, or working with a species that retains it - the answer is simple. I choose to keep my land. As you can see (above) I like to be ruthless with leucaena anyway. So it's high productivity, suits my quest for acquiring plentiful, soil improvements.

If leucaena shows up on your property, my advice is to use it (animal fodder, mulch, and preventing soil erosion) otherwise, remove it completely. Because what good is it to your land, if it takes over? And it will, if left unchecked. It's just one of those plants, which are really good, at self-replication.


  1. I think you're doing the right thing. You have to manage the land in a way that's best for it, given the prevailing conditions. It's the essence of what permaculture is about.

    With climate change on our doorstep we have no idea what native plants are going to survive as part of ecosystems. It's even possible that the Leucaena, while doing well now, won't do as well, decades down the track.

    It's doing a job and providing a resource for you that the local natives won't do any more. I'd say go for it!

    1. You're right about prevailing conditions, Bev, and ultimately determines what will grow anyway. The one weakness of Leucaena - as with other declared exotic weeds originating from Mexico, is the cold. So if we got more frosts, for longer, that would probably take it out. It's just not adapted for that.

      Although I wouldn't be surprised, if we've bred our own strain of Leucaena in Australia - as it arrived on my doorstep, via the spread of seed. So it tells me, for it to have moved from the tropics/subtropics, into more temperate climates, either the climate is getting hotter for them to reach weed status, or they're adapting to colder conditions.

      Probably a little of both. It's really fascinating what plants can do!

  2. This is a great post Chris. I totally agree with you about the benefits of your "so called" weed trees. All situations need to be looked at in their own unique circumstances, and not to just go ahead and make decisions based on a blanket measure. Peter Andrews, whose books you will have read, would be pleased with what you're doing there on your land. Oh if only more people saw this logic, as you have done, the land would be in far better shape.

    1. Ha-ha, yes! Peter Andrews came to mind, many a time, as I was watching this plant interact with our conditions, over the years. So did permaculture. Not that I used either to sway me, because I was happy to take out the leucaena, if I thought it was more a detriment than a benefit.

      Ultimately, that's what Peter Andrews and permaculture teaches us though. To be observant and intervene (or not) when it's in the best interests of the landscape. We've lost that knowledge in our culture. Thankfully, the information is there however, for those with an interest to do something - rather than just feeling helpless.

      I'm grateful for people like Peter Andrews, and the developers of permaculture. For their persistence and working models. Goodness, they've shaved years off my land rehabilitation - and I was already planning to commit a lifetime, lol. ;)

  3. Chris I think your being very responsible, you understand the plant your managing and and you have a long term management plan in place for it. The land is lucky to have you as a steward over it!


    1. Thanks, Emma. :)

      I'm looking forward to following your journey, should you make that leap to acreage, as you hope to. There will be discoveries to make, in a landscape, very different to my own. But I can still learn something from your sharing, I'm sure.

  4. Chris, such a good way to use an invasive plant on your land. Hopefully there will never be a repeat of the 2011 floods in our region.

    1. Absolutely, Chel. I would be happy if the rain started to come more consistently, in less amounts. Rather than all at once! Fast running water, chews up the land and hurts the living things upon it. I'll join you in that hope! :)

  5. You're are using it the way it is meant to be used (small huts and windbreaks could also be constructed out of it too under more primitive regimes). The problem is that 99.99% of people do not proactively use it like you - then its a problem.

    1. You make a good point. Most people wouldn't know a leucaena was an exotic weed, if it arrived on their doorstep. Let alone, how to use it's productivity to benefit their landscape. I certainly didn't know it was a weed, until the main tree, established itself.

      Is that reason enough to declare it a weed? I think it is - to the general population, at least. Those who have no use for it, should take it out. It will save them a lot of work, removing saplings. But what about those who could use it to naturally increase land productivity, without the use of chemical fertilisers? What if they could reduce silt, clogging up waterways too? The catch 22, is tricky!

      We should always follow the general rules - until a more pressing issue, requires us to reassess, on an individual basis. Thanks for adding more to the discussion. :)

  6. Seeing it as a resource & making good use of it in ways which keep it under control but also help you to manage and improve your land, is wise in my opinion. Meg:)

    1. Thanks Meg. It was certainly outperforming anything I could grow up there, lol. A resources is a gain, if the trend in that location, is to lose resources. So it made a lot of sense to use it, to help the others become retained. I only wish my other plants, could grow so well! ;)


Thank you for taking the time to comment. I love reading what you have to share. Gully Grove is a Spam free environment though, so new commenter’s only leaving hyperlinks, will be promptly composted.