Giant Miscanthus

Miscanthus × giganteus

Wow. What an incredible plant! Been reading about this stuff lately and I'm excited about the possibilities. It seems to me a multi-functional homestead superstar. Biomass, building material, bedding/mulch, fuel, windbreak, privacy screen etc. I love things that solve multiple problems simultaneously!

Perennial, a C4 photosynthesizer, and it grows to a dozen-ish feet tall or more each year, but can be grown on marginal land. Since it pulls all the nitrates and other goody bits down into the roots in the fall, what you harvest is pretty much pure carbon, so not much nutrition needs to be replaced in the soil each year. That combination of ultra high biomass yield and minimal fertilizer requirements almost seems too good to be true. Can anybody out there growing it confirm? Is it actually that good? Or have I fallen for the hype?

You end up with canes similar to small diameter bamboo, suitable for all manner of handycrafts - stakes, trellises, weaving into hurdles and such. Since it's small diameter, you likely wouldn't need much more than one of those little electric woodchippers to turn it into mulch, animal bedding and compost browns. The animal bedding particularly interests me, because my plan is to have ducks, and ducks have a reputation as messy, splashy poop machines. So I'll need bedding and lots of it. If I could grow my own bedding and not spend a lot of effort and soil fertility doing it that would be ideal. According to these guys shredded miscanthus bedding is "three times more absorbent than wood shavings, due to the porous pith inside the Miscanthus cane". Sounds interesting. Almost like the centre of the cane is filled with sponge or something. That gets me wondering what the R value of that spongy stuff is. Grow-your-own-insulation would be a neat concept. Anybody used baled miscanthus in stawbale construction applications? Seems like it would serve well there too.

It also seems ideal as a non-food crop through which to dispose of greywater as well as humanure compost from a compost toilet system. It allows you to recapture nutrients and water back into the garden system without having to apply any of it on or near food crops, which I'd like to avoid. In fact, I believe the provincial composting toilet guidelines only allow surface discharge of material from those units on non food crops, so if I run a composter I would need something like this anyway.

One application I'm brainstorming on right now is the possibility of using strips of miscanthus, maybe 5 or 10 feet wide, planted along the property lines. This would form a living fence, privacy screen and windbreak, but what really has me intrigued is the possibility of it serving as a firebreak. This would need a source of irrigation - perhaps a "waste" source like the greywater handling role I mentioned above - in order to make sure it has the moisture it needs to grow green and lush during the sketchiest parts of the forest fire season. I don't imagine it would burn when green, would it? Forest fire is a massive risk where I am. I've often thought of using strips of moist non-flammable plants (comfrey, for example) to act as a break against creeping ground fires, but with the miscanthus standing so tall it also might be able to trap/extinguish floating embers up to and including a dozen feet off the ground. That would be pretty great, if it works. I would love to learn more about the flammability of miscanthus at various stages of the year and growth cycle.

Anyways, I could go on and on. Stick stove fuel. Biochar feedstock. Maybe even substrate for cultivation of wood-loving mushroom species (anybody try it?). This plant seems to have endless usefulness to the homesteader. Is anyone out there growing it in southern BC? Does it do well here?

Given that it's burned for fuel, I doubt it would be good for fire protection. Just because it's still alive and green, doesn't mean it won't burn. But for the other things you mentioned it sounds good.

I just use oak leaves and hemp trim for my chickens, but maybe I'll need something more when I get ducks. Interesting idea.

yeah the firebreak concept is a bit of a half-baked idea at this point. If it's flammable green, then I'd just be surrounding myself with fuel.



This makes it look like the top half would be tough to light, but that bottom half looks awfully flammable...

I've never grown the stuff myself so I don't have hands-on experience with it. I've just been reading  all about it and have gone a bit miscanthus mad ha ha.

I kind of wonder how much it would spread too. It's a sterile hybrid so at least it's not going to bird-scatter all over the place, but those rhizomes will spread. Anyone here familiar with its spreading habit? Do new canes come up fairly near existing ones, or does it travel large distances underground and sprout up far away? I'd be interested in exploring whether there are known companion plantings for it, especially ones that might be able to function as a barrier species, keeping the borders of the patch in check without having to bust out the shovel and hack it back every year.

The miscanthus hybrid they planted around my part of the world loses its leaves every season and dies back , so i dont think its a good firebreak or privacy screen ,more of a camo screen as it could break up a the shape of a building more than hide it or totally screen something. Its harvested once the leaves die off and chipped ,warm air dried and compact baled into 200 liter ---by volume ---or 25 kilograms by weight plastic bags ---has to be carefully sifted and dust removed if sold as horse bedding---as a diy enterprize needs some large equipment and shed space or a good drying season if left out in fields, does not have that much feed value for animals so good in that regard --nothing really wants to eat it ---but i would not trust goats with it. I use it in my dog kennels as bedding and works very well , use as plant mulch does great for that  ,use it as hemp substitute for crete --insulation  but i dont grow it ---its kind of cursed around our way---farmers all swear at it ---also dont have enough acres to grow enough of my own. Large scale planting needs the corms of it and modified potato planting machines--its sterile so although sets a seed they are not viable---yet---nature can be clever

Forgot to mention, i also use a blend of chipped m/grass and pine needles in my composting toilets and i have started on building a bubafonja type stove that could morf into a sawdust burn type stove hybrid which can burn something like chipped m/grass , having to buy in chipped grass would not be a cheaper option for me , it maybe cheaper than wood /biomass pellets , which i have no intention of using ,i dont want to tie into that market product.

Storing it would need a decent area under a roof I suppose... unless I wanted to shred it all at once at harvest, which seems like a big task and even then, the shredded result would also need to be kept dry. Seems like less hassle to store it as whole canes and shred it as needed. It wouldn't be much more than just a roof on stilts with minimal walls or even none at all. Maybe some simple racks to help use the vertical space. Simple and cheap(ish) to build, and another rain capture surface couldn't hurt.

Fuel pellets for an auto-fed stove would be an interesting application, but would need a pretty fine initial grind, then a pellet machine to re-compress them, and presumably you'd also need some sort of binder. That seems like a lot of machinery and energy use. What about just a rough chop into small sections? Such that the ratio of length to diameter is roughly the same as a standard wood fuel pellet, but it's just a chopped cane piece with no further processing needed. Size would be far larger than a standard pellet, density far lower, so it wouldn't work in any standardized system. You'd pretty much have to design your own stove, with a custom hopper/feed auger system. And I guess you'd have to build the custom chopper too.

As mulch, I wonder what the effect on pH would be. Wood shavings, barkmulch, sawdust and such tend to lower pH, each by different amounts. Anybody know how shredded miscanthus compares in that regard?

Hi, I have about 140 clumps of miscanthus Giganteus on May 17 acres. Every one of them came from a clump given to me by a friend about 20 years ago. They have lots of uses but do not invade anything in zone 6b. My mother patch is no more than 8 feet in diameter.

They are truly a wonderful plant and all of the positive uses mentioned are definitely positive possible uses. I use them for helping to define fairways on my disc golf course. I also find that they are a wonderful protection for planting other trees inside. Growing inside 6 foot wide clumps of miscanthus I have elms, willows, pines, black walnuts, mulberries, etc. One year, a few years ago, I moved several clumps, well maybe a dozen or two or three 🙄 and I planted a willow cutting in the middle of each one. Now the thriving clumps are about 4-6feet across and 12-13 foot tall but the willows in each one are over 20 feet.

Danger: They are terribly flammable. One of the reasons they’re a good source of bio fuel mass is because standing, in the spring, they have as low a water percentage as any other plant that exists. But that means they’ll go up almost like they’re filled with gasoline. I’ve become careful about where I put mine, given prevailing winds, because of what they might burn close by if they got started. And my wife loves to go out and burn them for fun.

Hey Mike.
Your ideas on using this plant for fuel made me think it could be used in a TLUD biochar stove.
Chopped to a standard length, it could be used as "pellets" without needing an auger.
It could also match well with pocket rockets, a very simple type of rocket stove that has the virtue of allowing very long fuel to be used in the feed tube without back draft occurring.

Terry Paul Calhoun wrote:Danger: They are terribly flammable. One of the reasons they’re a good source of bio fuel mass is because standing, in the spring, they have as low a water percentage as any other plant that exists. But that means they’ll go up almost like they’re filled with gasoline. I’ve become careful about where I put mine, given prevailing winds, because of what they might burn close by if they got started. And my wife loves to go out and burn them for fun.

Yeah leaving them standing dry would be a fire hazard for sure. I'm assuming that in the spring and summer when they're green and still growing they'd be pretty hard to burn. What time of year would you say that the transition to flammability happens?

William Bronson wrote:It could also match well with pocket rockets, a very simple type of rocket stove that has the virtue of allowing very long fuel to be used in the feed tube without back draft occurring.

That's the best idea of all, because it wouldn't require any processing whatsoever! Just stick the whole cane in and let it slide down the feed tube as it burns.

Seems like the grass would make awesome "wood chips" for the gardens.

Yes it does work for mushrooms!

Oyster mushrooms can benefit from the meat substitution trend
This is an article about growing oyster mushrooms as a protein source in vegetarian and vegan diets, and it mentions this company using a mixture of shredded miscanthus and straw as their substrate.

Safe and sound: Decentralisation with Miscanthus giganteus
This one is about the more large scale industrial uses for miscanthus as feedstock for decentralized generation of combined heat and power, pulp and paper applications, and bioplastics. But it also contains a mention of using it for mushroom cultivation. Oysters again, but they also mention growing shiitakes on it, which is rather intriguing.

My personal experience is still quite limited, I think it was three years ago when I planted root cuttings. It hasn't really spread for me. More relevant though, several years back someone near me was going to start making "wood" pellets from it. That fell through and they found another use to sell it for, but there are now several fields of it in the neighborhood. In ten or fifteen years, I've never seen it spread to anywhere else.

Just found this the other day. I don't think it's spread so much as it's grown into a full sized plant, but it was planted beside a railroad tie and now has two stems on the other side of it.

T Melville wrote:Just found this the other day. I don't think it's spread so much as it's grown into a full sized plant, but it was planted beside a railroad tie and now has two stems on the other side of it.

Good to know! I was worried it would be like raspberries, which I've seen shoot up new canes 15-20 feet from an established patch. Those railroad ties are usually pretty chunky aren't they? 6-7in deep? Seems a subsurface barrier would need to be deeper than that to be effective, but I guess if it spreads that slowly it's not exactly threatening to get out of control and take the whole place over or anything!

I looked a bit further into using it in strawbale construction, and I came across this article about it:
Miscanthus: the game-changer in building construction
It's written by a group that markets and promotes miscanthus in the UK, so they're tooting their own horn a bit here, but they seem quite chuffed about the compression strength and thermal/acoustic insulation properties. Seems like it would work pretty well, and since you can grow it yourself in quantity on marginal land it may turn out much cheaper than paying to truck in bales of grain straw.

Read that article, and they want to develop a fertile seed based miscanthus, why ? , ,just another problem to deal with when it escapes , wont be popular around sorghum growers or sugar cane , as that will create hybrids, good to see it being used as an alternative to straw bales though ,its possible to use it as feed stock for bio refinery and butanol production but thats all out our backyard /in the shed capabilities. It was chipped and dried in ireland to supply furnaces /steam/electricity ,thats were the farmers came into it , it all ended in tears/swearing, as the furnaces stopped taking it in very suddenly and abandoned the whole scheme. For home/farm use maybe square bale it and build a furnace heater for it like the giant hay  bale burning ones that featured sometime ago on some large european estates and farms.

Hi, I live in Austria and I planted 100 Miscanthus plants a couple of years ago, and I can confirm that this is a really practical multi-purpose plant. I use it mostly for garden paths, but also for animal bedding (ducks) and heating. It's a really good mulch, but I've noticed that bushes aren't too pleased with it, either because it suffocates the ground too much, or because it attracts certain weeds. Voles and mice on the other hand love it, probably because of its excellent insulating properties. I put heaps of Miscanthus (or Elefantengras as it's called in German) around a young walnut and apple tree, and the mice said thank you for the winter warmth and destroyed the roots.

But anyway, one downside for me as a non-farmer, is that it's a lot of (dusty) work to shred the reeds into small bits. I use a Makita UD2500 electric shredder that uses rotation gears (rather than knives). About a third of the reeds I put in, are transformed into nice small bits, but the rest consists of long stems that the shredder didn't quite manage to cut. It makes the work rather cumbersome, as I have to do extra rounds for those half-cut stems/sausages, and it actually works best when the machine is almost jammed, which is why I only empty half of the container below the shredder.

I now use those half-cut stems to get my wood over fire going (it burns great). 100 plants is more than enough for my needs, and I'm actually planning to find different uses for the yearly harvest (they get really high, like 3-4 metres), such as biochar or basket weaving.

If anyone has any tips on how to shred Miscanthus faster, I'm all ears. Just wanted to share my experiences.

If anyone has any tips on how to shred Miscanthus faster, I'm all ears.

Interesting insights on the shredding. I had assumed that it would shred really easily due to the small diameter and the fact that it's a large grass rather than a tree branch. Less dense and presumably easier to shred than a branch of the same diameter? But I guess it depends on the cutting type. I can see how the kind with the gears could have trouble, since it's more of a crush than a slice.

From a quick search, most of the info out there about shredding miscanthus seems to be aimed at commercial operators and enormous industrial units. Maybe since it's so similar to bamboo, figuring out which home unit is best for that would lead to better results? Then again, a lot of that info is about shredding *green* bamboo, which is not really a great analogue.

I'd like to report back and post an update on my attempts to improve my processing process of Miscanthus x giganteus.  

As I wrote last year:

I use a Makita UD2500 electric shredder that uses rotation gears (rather than knives). About a third of the reeds I put in, are transformed into nice small bits, but the rest consists of long stems that the shredder didn't quite manage to cut.

The alternative to rotation gears (or cog wheels) are knives, but in most shredders this actually consists of a disk with two openings and two small (similar to razor) blades mounted next to the opening. After scouring the Internet for customer reviews, I concluded that the reeds would almost certainly get between the gaps around the disk and thus cause the motor to stop spinning.

Luckily, there was yet another alternative, but it seems to be an older standard that is hardly found in modern shredders (or at least, not where I am): two or more spinning knives on top of the vertical motor axle. I managed to find a Viking shredder that was over 20 years old, but very well maintained by a retired mechanic. In the attachments, there's a picture showing the Makita and Viking.

This system with spinning knives is much more suited for shredding reeds. Whereas the Makita cuts the reeds and you get small pieces of reed, the Viking really shreds them to bits, and you get these elongated narrow 'shards'. But no clogging unless the bin is full. For results, see the second attachment with Makita on top, Viking in the middle, and the two compared on a garden path at the bottom.

The only 'downside' of the Viking is that you have to hold the reeds and slowly drop them, or else the centrifugal forces cause the reeds to turn at high speed, whack you in the head and then be spit out. By holding the reeds, you also control the shredding a bit, in that the shards don't get too long. All in all, it's much easier than with the Makita, where I had to kneel down every 2 minutes, put my arm in the bin to unclog the cog wheel from below. What used to take me at least a week (4 hours a day), was now done in a day or two. Mind you, the Viking's power requirements are half those of the Makita (1300W vs 2500W), so much more efficient in that sense as well, saving energy all around.

BTW, I shred the Miscanthus leaves with a lawnmower, and the result is great for mulching and bedding (see third attachment).

Another thing I improved, was the harvesting process. I used to do it with a hedge trimmer, like these guys in Wales:


This, however, is extremely tedious and time-consuming because every time you cut a stalk, it just drops down and doesn't fall over because of the other reeds, so you keep cutting over and over again, and the trimmer obviously gets clogged all the time (granted, my trimmer isn't very powerful). You're also close to where you're cutting and thus constantly breathing in the reed dust. I decided to take a risk and invest some money in a Makita brush cutter (DUR368) that I could use for other stuff as well. I also bought the blade that is probably best suited for the job (see fourth attachment). I was lucky here too, and what used to take me days and days, was done in one whole day.

All in all, these two improvements have a big impact on the time and energy it takes me to harvest and process around 100 Miscanthus plants (around two cubic metres of shredded material). I use them mostly for garden paths, for bedding in a duck coop, and for getting fires going. Next, I'll be looking into biochar.

PS I forgot to say that you need the cover of the bin that the Viking shredder expels into, or else it'll be all over the place (see bottom picture in last attachment).

It seems some more videos on YouTube have appeared over the past few months that show how people shred the stuff. Here's a French guy demonstrating both a shredder with a 'cog wheel' and one with a blade-studded disk:

Neven Curlin wrote:I'd like to report back and post an update on my attempts to improve my processing process of Miscanthus x giganteus.

Great info. Thanks! Sounds like the cutting blade type is the way to go instead of the crushing gear type.

In perusing the board for more shredder stuff, I did come across the does paul hate wood chippers thread, which is an interesting alternate take. Any machinery ultimately creates dependencies on maintenance, spare parts and energy. I guess in the end the most natural, permie-style way to break down woody biomass like this is to take a cue from nature and use fungi, at least as a backup for if the day ever comes where the shredder kicks the bucket.

It wouldn't be all that suitable for animal bedding or paths, but it would at least process it without machinery, generate an edible yield and get the carbon into the soil as spent mushroom substrate. Yet every source of information about cultivating mushrooms on miscanthus uses pre-shredded material. Makes me wonder... Could something like winecaps - which can be grown outdoors on non-pasteurized substrate - be set up to grow on whole miscanthus canes?

Mike Fullerton wrote:

Neven Curlin wrote:I'd like to report back and post an update on my attempts to improve my processing process of Miscanthus x giganteus.

Great info. Thanks! Sounds like the cutting blade type is the way to go instead of the crushing gear type.

In my case, definitely. I've posted an attachment to show how the old Viking shredder is built up, so as not to confuse it with modern shredders that sport a (usually) diagonal disk with blades on them.

In perusing the board for more shredder stuff, I did come across the does paul hate wood chippers thread, which is an interesting alternate take. Any machinery ultimately creates dependencies on maintenance, spare parts and energy.

Absolutely true, but once you choose to use a machine, there are gradations as well. From buying a brand new 500 hp diesel-burning monster to buying a second-hand 1300W Viking from 2000. But it'll always involve dependencies (everything does).

Of course, it all depends on the use case as well. The discussion you link to concerns wood chipping for garden use. When it comes to Miscanthus, my use case is primarily for garden paths, as wood chips lower soil pH. Secondary uses are stable bedding (mostly leaves), kindling and biochar. But without a shredder, it would be nigh impossible to use Miscanthus for garden paths.

Could something like winecaps - which can be grown outdoors on non-pasteurized substrate - be set up to grow on whole miscanthus canes?

All I know, is that when I don't have time to immediately process my 2 m3 heap of canes, some lovely fungi start to form after a couple of months. I don't know anything about mushrooms, but I'm sure unshredded Miscanthus could be used for something.

Miscanthus  giganteus is definitely impressive, but yeah… it’s not quite as magical as it sounds on paper.

The yield part is real - it can put out a ton of biomass once established, and it doesn’t need heavy inputs every year. But the ‘grows on marginal land with no downsides’ angle is a bit oversold. It still needs decent moisture to really perform, especially in the first couple of years while it’s establishing.

For bedding and mulch, it’s actually a solid use. The absorbency claim isn’t totally crazy -the pithy core does help. A lot of people in Europe use it for animal bedding with good results.

Where I’d be more cautious is firebreaks - dry miscanthus is basically tinder. Green, irrigated stands might resist ignition somewhat, but once it cures out, it can carry fire pretty fast. I wouldn’t rely on it as a primary firebreak without serious management.

Also worth noting: establishment can be slow and not cheap (rhizomes), and it doesn’t spread aggressively because it’s sterile, so you’re planting everything intentionally.

For southern BC specifically  it can grow there, but performance will depend a lot on your rainfall/irrigation. In drier areas, it won’t hit those “giant biomass” expectations without water.

Overall though, as a multi-use biomass crop? Yeah, it’s legit - just not quite the miracle plant some articles make it out to be.