Birdsfoot Trefoil and Sainfoin: The Non-Bloat Legumes for Ground Alfalfa Hates

By the XES Netting team — bale net-wrap manufacturer · Updated August 11, 2026 · ~15 min read

Most producers meet these two legumes the same way: alfalfa fails on a field, someone mentions a name they half-remember, and the search begins. The information that comes back is thin and often contradictory — including on basic questions like whether trefoil dries faster or slower than alfalfa, which working hay producers answer both ways.

This guide sorts that out. It draws on the published agronomy from Montana State University and the North Central Regional extension programme, and on a decade of first-hand accounts from producers actually growing these crops. Where they disagree we say so, and where the forums have it wrong we say that too.

Why look past alfalfa at all

Alfalfa is the highest-yielding perennial forage legume in most of North America, and if your ground grows it well, grow it. These two crops earn attention in four situations:

• Wet or acidic ground where alfalfa drowns or sulks — trefoil's home territory.
• Bloat risk on pasture, especially with grazing dairy cows or sheep, where neither of these will bloat stock.
• Dryland at elevation in the intermountain West where one or two cuttings is the ceiling — sainfoin's home territory.
• A wider harvest window, because both hold feeding quality later into maturity than alfalfa does.

That last point is the one producers underrate. As one North Carolina hay grower put it when explaining why he was trying trefoil at all:

My main reason for wanting to try trefoil is I have read it is supposed to hold its quality in the field and not get over mature as fast as alfalfa which would allow me a wider harvest window. Mature alfalfa is very difficult for me to sell.

— FarmerCline · HayTalk thread 83185

He read correctly. The North Central Regional Extension Publication 474 confirms trefoil's digestibility is similar to alfalfa at comparable maturity but that trefoil maintains higher quality as it advances. Montana State reports the same for sainfoin: it retains its leaves longer than alfalfa and can be cut at 50% bloom without losing nutritive value.

Birdsfoot trefoil: what it is and where it wins

Lotus corniculatus is a perennial legume, 12 to 30 in. tall, well adapted to the north-central states. Its real advantages are specific:

• Tolerates poorly drained and acidic soils that make alfalfa production difficult. This is the single biggest reason to plant it.
• Does not cause bloat, thanks to condensed tannins — which makes it an unusually good pasture legume for grazing dairy cows.
• Reseeds itself naturally. Pods shatter and disperse seed, so stands persist far beyond the life of individual plants.
• Excellent grazing tolerance, particularly the prostrate types.

The limits are equally specific, and two of them catch people out. Trefoil will not survive where standing water persists into summer or where ice sheets form in winter — "tolerates wet" is not "tolerates flooded." And because its taproot is branched and relatively shallow, it is less drought tolerant than alfalfa, which surprises people who assume a tough legume is tough in every direction.

Heat is the other wall. A Virginia producer summarised where the crop stops:

Typically the weak spot for trefoils is hot southern summers. It has typically done much better a bit further north. Other than that, it handles soil challenges that southern farmers face pretty well. So, if we could get a more heat-tolerant variety, I’d be very interested.

— reede · HayTalk thread 83185

That is exactly what the variety work addresses. Trefoil varieties fall into three groups: prostrate grazing types (AU-Dewey, Dawn, Empire, Fergus, Leo), erect hay types (Georgia-1, Maitland, Viking), and semi-erect (Mackinaw, Norcen). If you are cutting hay, start with the erect group. Norcen carries the best winterhardiness; Viking has excellent seedling vigour and the earliest maturity; Georgia-1 was selected for acid-soil tolerance and AU-Dewey for the south-east, though AU-Dewey's winterhardiness is only low to moderate. Empire and Viking date from 1930s New York — still sold, but newer varieties have better seedling vigour and disease resistance, which is precisely where trefoil is weakest.

The establishment problem — and the seeding rate nobody mentions

Trefoil's fatal flaw is that its seedlings are small, slow and cannot tolerate competition. Almost every failure in the producer accounts traces back to this. It is why overseeding into existing sod so rarely works:

Birdsfoot Trefoil is very difficult to overseed into an established pasture. It is slow to establish and does not compete well with existing grasses or legumes. I have introduced it into existing stands with no till seeders but had poor results given the expense of seed and cost of the seeder.

On the other hand it has done very well when I planted it on new prepared ground with a Brillion seeder mix of grass and clover. It will tolerate wet and acidic soils better than other legumes. It should also be allowed to flower in the the initial year before grazing or mowing.

— Fossil02818 · HayTalk thread 22799

The most useful single piece of advice in the entire corpus comes from a seed producer who has watched a lot of stands go in, and it is not in most extension bulletins:

One thing to keep in mind is that it is a very weak competitor during establishment, and in mixtures, you may not really know what kind of BFT stand you have until the 2nd or 3rd year.

Due to its slow establishment and weak competitiveness, I usually recommend seeding twice as many pounds of BFT as what you would alfalfa. BFT seed count is about 1.75 times higher than alfalfa, but in my experience it takes 2 lbs of BFT seed to equal 1 lb of alfalfa seed to get the same number of viable plants.

— prairie · HayTalk thread 25185

Note the second half of that: trefoil seed is smaller than alfalfa seed, so a pound contains more seeds — and yet you still need twice the poundage to get the same plant count. That gap is pure establishment mortality, and budgeting for it is the difference between a stand and a disappointment.

Published seeding rates are for pure live seed, so adjust for germination and purity:

Source: NCR Extension Publication 474. Producers commonly run heavier — 12 lb pure, or 16 lb trefoil with 4 lb grass — which is consistent with the doubling advice above.

Three more establishment rules worth following. Seed into a firm seedbed with genuine seed-to-soil contact. If you use a small-grain nurse crop, pick a short variety at 1 to 1.5 bu/a and remove it at boot stage. And for frost seeding, go in early spring while the ground is still frozen — extension work finds fall and overwinter seeding often less effective, because wildlife eat the seed and thaw runoff carries it away. One producer lost an entire fall seeding to a 3 in. rain two days after planting, which is the same failure by a different route.

The dry-down argument — and why both sides are right

Here is the question that generates the most contradiction, because producers report it in opposite directions with equal confidence. Faster:

Here I just fall planted some at 5lbs trefoil, 5lbs orchard grass. I could not be happier with yield this second year. Faster drydown than alfalfa, the stems are smaller. Mike

— HayMike · HayTalk thread 76514

Slower:

I planted bf trefoil with timothy and had excellent results. Trefoil will stand trampling much much better than alfalfa and as you said doesn’t loose TDP if not cut at its peak. Also does well in wettish fields.

Takes about 1/2 to 1 whole day longer than alfalfa to cure and you must use a conditioner set to really crimp the stalks as they are waxy.

— Trillium Farm · HayTalk thread 83185

And no different at all:

I mix birdsfoot in with the timothy that I seed (2:1 timothy to birdsfoot) and plant in the fall. This seems to give the birdsfoot enough time to get established prior to the fall freeze and then it takes off the following spring.

As far as getting it to dry down, I haven’t noticed much of a problem, but that might be because I have it mixed in with timothy. Usually we can rake/bale on the second day after we mow (disc mower w/ conditioner) without any problems on first cutting, second cutting takes another day or two, but I blame that on the shorter/cooler days we get later in the year.

— Josh in WNY · HayTalk thread 25185

The mechanism that reconciles all three is a detail about the plant itself:

Trefoil has a waxy substance on its stems and if not conditioned the leaves will dry out before the stems are ready. Even so it’ll take a day longer than alfalfa.

I conditioned mine with rubber rolls, nowadays you have flail in steel and plastic this may do a better job on the stems, but I don’t know what it will do to the leaves.

— Trillium Farm · HayTalk thread 25993

Put the three reports side by side and the pattern is clean. Trefoil stems carry a waxy cuticle that holds moisture; trefoil leaves are small and dry fast. So:

• Trefoil-dominant, unconditioned → the leaves are bone dry while the stems are still tough. You bale tough stems or you shatter the leaves waiting. This is the "slower than alfalfa" experience.
• Trefoil-dominant, well conditioned → crimping breaks the wax layer and the gap closes to roughly half a day to a day behind alfalfa.
• Grass-dominant mixes (the 2:1 timothy blend above, or 5 lb + 5 lb with orchardgrass) → the sward behaves like grass hay and the wax barely registers. This is the "faster than alfalfa" experience.

So the practical rule is not "trefoil dries fast" or "trefoil dries slow." It is: the wetter the trefoil fraction, the more the conditioner matters. If you are running a trefoil-heavy stand, set the conditioner aggressively on the stems and expect an extra day. If you are running trefoil as the legume component of a grass hay, do not expect a dry-down penalty at all. Our guides to making dry hay faster and disc mower vs mower conditioner cover the machinery side.

Weed control: the bind that isn't

One concern comes up repeatedly, and it deserves correcting because it stops people planting a crop that would suit them:

I’ve read it’s it is a good Timothy companion crop as was already mentioned. I’ve considered it, but struggle how you’re supposed to use a broad leaf herbicide with your grass and not wipe out the legume.

— VA Haymaker · HayTalk thread 76514

The answer he got in the thread was, in effect, you don't — burn it down and replant every four or five years. That is a legitimate strategy, but it is not the only one, and the extension literature is clearer than the thread was.

2,4-DB (Butyrac) is labelled for use on seedling and established birdsfoot trefoil. It is a post-emergence systemic that controls many annual broadleaf weeds and — the point that resolves the dilemma — will not control grasses. In a grass-trefoil stand it leaves both the grass and the legume standing. Do not confuse it with 2,4-D, which will kill the trefoil.

The real limits are different from the ones producers worry about:

• It is weak on mustards and smartweed — so if yellow mustard is your problem, this is not your tool.
• Timing is critical: apply when seedling weeds are no more than 3 in. high. Control falls off fast on larger weeds.
• There is a 60-day harvest and grazing restriction after application. Plan the cutting schedule around it.
• For grass weeds, Poast Plus is the companion. Extension guidance is that tank-mixing it with 2,4-DB increases the risk of crop injury, because the oil concentrate raises 2,4-DB uptake — apply the 2,4-DB first and the Poast Plus seven or more days later.
• Balan (benefin) is a preplant incorporated option, but do not use it if you are seeding forage grasses, because it will kill them.

Always read and follow the label for your state and product; rates and restrictions change. More on the general problem in weed control in hay fields.

Stand life: why trefoil outlives its own seeding

Trefoil's individual plants are not especially long-lived — typically about two years in central and southern states, longer in the north. Yet stands routinely outlast alfalfa by a wide margin, and producers report some remarkable ages:

There are trefoil stands 40 yrs old. Naturally they are in ideal conditions

— Trillium Farm · HayTalk thread 25993

The explanation is reseeding, not plant longevity. Trefoil flowers over three to eight weeks, the ripened pods shatter, and the seed disperses itself. Extension guidance is explicit about how to exploit this: allow the stand to flower and set seed at some point during the growing season, particularly in years when the stand is thin. Producers arrived at the same rule independently — one lets it go to seed every year deliberately.

It works well enough to be inconvenient. One producer reseeded a field without trefoil in the mix and reported the trefoil still going strong afterwards.

Two more management points support persistence. Leave adequate stubble — extension trial data shows regrowth yields were significantly better cutting to 3 or 4.5 in. residual than to 1.5 in. And know that trefoil is susceptible to root and crown rot, which is why newer varieties such as Dawn were bred specifically for resistance.

Sainfoin: the dryland West's non-bloat legume

Onobrychis viciifolia is an entirely different proposition — a deep-rooted perennial adapted to the Rocky Mountain region, growing to 3 ft or more, somewhat taller than alfalfa. The French sainfoin means, roughly, wholesome hay.

What Montana State University establishes about it:

• Non-bloating, and unusually palatable — MSU pasture studies found cattle and sheep prefer sainfoin to other legumes.
• Yields as well as or better than alfalfa in many production environments. Irrigated Montana trials ran 2.95 to 4.44 t/a dry matter; dryland sites ran 0.85 to 1.72 t/a.
• Equal to alfalfa in feed efficiency and digestibility for beef cattle, and equivalent in swine diets when ground. Higher in carbohydrates, lower in crude protein, fibre and ash.
• Holds quality — retains leaves longer than alfalfa and can be cut at 50% bloom without loss of nutritive value.
• Stems look coarse but are soft and readily eaten by all classes of livestock.

Establishment is where sainfoin differs most sharply from everything else you plant:

• Soil pH 7.0 to 8.0 — neutral to slightly alkaline. This is the opposite of trefoil's niche.
• Huge seed. A pound of dehulled sainfoin holds roughly 32,400 seeds against about 220,000 for alfalfa. Hence the rates: 34 lb PLS/a dryland, 45 lb irrigated for pure stands.
• Shallow planting despite the big seed — 1/2 to 3/4 in. Sainfoin does not emerge from deep planting, so use depth bands.
• A sainfoin-specific Rhizobium inoculant is mandatory. Alfalfa and other legume inoculants do not work. This is the most common avoidable failure.
• No small-grain nurse crop. Sainfoin seedlings are vigorous but do not compete with cereals. Control weeds by mowing, grazing or herbicide instead.
• In mixtures, plant sainfoin and grass in alternate rows.

Note how completely that inverts the trefoil playbook: acid versus alkaline, tiny seed versus large, nurse crop acceptable versus not, doubled seeding rate versus a published rate you should actually follow.

Where sainfoin fails

Two hard limits, and both are well documented.

Crown and root rot is the crop's defining problem. MSU names three bacterial and two fungal pathogens and reports that more than half of plants are infected within six months of planting. Rots move down the hollow stems into the crown, and yields generally decline in the fourth or fifth season under irrigation — though some Montana fields have persisted over 20 years. A producer reading the same MSU publication reached a sensible conclusion:

Interesting article. Did not realize the level of root and crown rot infection in 1st plantings. My focus is not large scale production; therefore, the upfront investment is reasonably small. So, loss of the sainfoin after 5 years would still amount to success.

I am interested in increasing my timothy hay yields, decreasing my nitrogen fertilizer inputs and creating an additional food/pollen source for our honeybee production.

— 2ndWindfarm · HayTalk thread 63097

That is the right frame. MSU's own recommendation is that sainfoin now be used only for short-term rotations in pure stands, or in grass-legume mixtures that persist after the sainfoin declines — and the companions it names are alfalfa, birdsfoot trefoil, meadow bromegrass and orchardgrass. Plan for the stand to fade and for something else to carry the field.

Geography is the second limit, and the most precise account of it in the corpus comes from a Nebraska seed grower who has sold sainfoin into several states:

While it does OK here on my farm under managed grazing, it is probably adapted to areas farther west than I am. It does not respond to fertility and extra moisture like alfalfa would, and it seems to struggle under the higher humidity as you travel east from the more traditional use areas in NM, CO, WY, MT. It does very well at higher elevations, 4k and higher.

If you can raise three or more cuttings of alfalfa, you probably have no reason to consider sainfoin. In areas where one cutting of alfalfa are the norm, sainfoin is likely a better option. In a two cutting system, sainfoin may be be very comparable. It does require a specific inoculant to thrive and fix nitrogen.

— prairie · HayTalk thread 18694

That cutting-count test is the most useful single screen we have seen for this crop, and it squares with MSU's variety guidance: Eski is recommended for dryland at 13 in. or more of precipitation and for irrigated ground yielding only one to two cuttings, while Remont — bred from Iranian material for rapid regrowth — is the choice for two- and three-cutting areas. Melrose is winter-hardy but slow to regrow; Renumex was selected in New Mexico for hot, dry Southwestern conditions.

Bloat, tannins and the parasite question

Both crops owe their non-bloating character to condensed tannins, which bind soluble protein in the rumen and prevent the stable foam that causes pasture bloat. That much is settled, and it is the strongest single reason to plant either on grazing ground.

The tannins have a second effect that circulates in a badly distorted form. You will see sainfoin described as a natural dewormer — one producer in the corpus called it "a cow dewormer as it disrupts their cycle." That framing overstates it. What peer-reviewed work actually supports:

• Condensed tannin forages, including both of these, measurably reduce faecal egg counts and worm burdens of gastrointestinal nematodes.
• Most of the strong evidence is in sheep; cattle data is thinner and responses appear less pronounced.
• They suppress rather than eliminate infection, and the size of the effect varies with tannin concentration, cultivar, maturity and the rest of the diet.
• They belong in an integrated parasite management programme alongside pasture rotation, genetics and judicious anthelmintic use — not as a replacement for one.

Treat a reduced worm burden as a genuine agronomic bonus, and keep making parasite decisions with your veterinarian and faecal egg counts rather than with a seed catalogue.

One more shared benefit worth naming: both are excellent pollinator forage. Sainfoin's rose-pink racemes in particular make it a favourite with beekeepers, and more than one producer plants it partly for the hives.

Choosing between them

They are not really competitors. Outside a narrow overlap, geography decides for you — and MSU explicitly lists trefoil as one of the mixture partners that can carry a field after sainfoin declines, so on the right ground the answer is both.

Baling and storing the crop

Two harvest characteristics matter once the crop is in the swath.

Condition the stems, protect the leaves. Both crops carry their feed value in leaves that dry ahead of the stems — the wax on trefoil stems, the leaf retention on sainfoin. Set the conditioner to work the stems properly, and do your raking and handling while there is enough moisture in the leaf to avoid shattering. This is the same discipline alfalfa demands, applied to a crop with a wider harvest window to work inside.

Because both hold quality later into maturity, you are less likely to be forced into baling marginal hay to hit a maturity target — which is exactly when hay gets baled a little tough. If you do end up on the damp end, our guides to baling moisture for net-wrapped bales and storing round bale hay cover the consequences and how to limit them.

Where XES fits: we make bale net wrap, and the honest connection here is a narrow one. Fine-stemmed legume hay — which both of these are, trefoil especially — sheds leaf every time a bale is handled. Wrap that covers the full bale width and holds firm shoulders keeps the outer layers intact through storage and loading, and the outer layers of a legume bale are where the leaf loss shows up first. That is a real benefit on high-value fine-stemmed hay, and it is not a substitute for cutting, conditioning and baling at the right moisture. If you are deciding how much coverage a crop like this justifies, see how many wraps per bale.

Frequently asked questions

Does birdsfoot trefoil cause bloat?

No. Unlike most legumes, birdsfoot trefoil does not cause bloat in grazing animals, because of the condensed tannins it contains. Combined with high forage quality, grazing tolerance and natural reseeding, that makes it one of the best pasture legumes available, including for grazing dairy cows. Sainfoin is likewise non-bloating.

Is birdsfoot trefoil better than alfalfa?

Not generally — alfalfa out-yields it on ground that suits alfalfa. Trefoil wins specifically on poorly drained or acidic soils, on grazing ground where bloat is a risk, and where a wider harvest window matters, since it holds quality better as it matures. It is less drought tolerant than alfalfa and does not survive hot southern summers.

How long does a birdsfoot trefoil stand last?

Individual plants often live only about two years in central and southern states, and longer in northern ones, but stands persist far longer through natural reseeding — producers report stands lasting decades. To get that, let the crop flower and set seed at some point in the season, especially in years when the stand is thinning.

What herbicide can I use on birdsfoot trefoil?

2,4-DB (Butyrac) is labelled for seedling and established trefoil and controls many annual broadleaf weeds without harming grasses, so it works in grass-trefoil mixtures. It is weak on mustards and smartweed, must be applied when weeds are under 3 in. tall, and carries a 60-day harvest and grazing restriction. Do not use 2,4-D, which will kill trefoil. Always follow the label.

Why did my birdsfoot trefoil seeding fail?

Almost always competition. Trefoil seedlings are small, slow and poor competitors, so overseeding into established sod rarely succeeds and thin stands are common. Plant into a firm, prepared seedbed, seed at roughly twice the poundage you would use for alfalfa, keep companion grasses light, and allow the stand to flower in its first year before grazing or mowing.

What seeding rate should I use for sainfoin?

Montana State recommends 34 lb of pure live seed per acre on dryland and 45 lb under irrigation for pure stands — far higher than other legumes because sainfoin seed is very large, at roughly 32,400 seeds per pound versus about 220,000 for alfalfa. Plant 1/2 to 3/4 in. deep and use a sainfoin-specific inoculant.

Why do sainfoin stands die out?

Crown and root rot. Three bacterial and two fungal pathogens are involved, more than half of plants are infected within six months of planting, and yields typically decline in the fourth or fifth season under irrigation. Plan sainfoin as a short-term rotation, or seed it in a grass-legume mixture that persists after the sainfoin fades.

Can I plant sainfoin with a nurse crop?

No. Although sainfoin seedlings are vigorous, they do not compete well with cereal grains, so a small-grain companion crop is specifically not recommended. Manage seedling-year weeds by mowing, grazing or with herbicides instead. This is the opposite of birdsfoot trefoil, which tolerates a light, short small-grain nurse crop removed at boot stage.

The bottom line

Neither of these crops is a general-purpose alfalfa substitute, and anyone selling one as such is overselling. What they are is precise answers to specific problems.

Plant birdsfoot trefoil if you farm wet or acidic ground in the northern half of the country, want a pasture legume that will not bloat stock, and can accept a slow, expensive establishment year in exchange for a stand that reseeds itself more or less indefinitely. Seed heavy, keep the competition off it, and let it go to seed.

Plant sainfoin if you farm dryland at elevation on neutral to alkaline soil where alfalfa gives you one or two cuttings. Buy the right inoculant, skip the nurse crop, plant shallow, and go in knowing that crown rot will likely end the stand in five years — so seed the mixture that will carry the field afterwards at the same time.

And with both, the reason to bother is the same: on the ground they suit, they do things alfalfa cannot.

Sources: Undersander, D., L. Greub, R. Leep, P. Beuselinck, J. Wedberg, D. Smith, K. Kelling, J. Doll, D. Cosgrove, C. Grau, S. Peterson, M. Wipfli and J. English, Birdsfoot Trefoil for Grazing and Harvested Forage, North Central Regional Extension Publication 474, University of Wisconsin-Extension · Cash, D., H. Bowman and R.L. Ditterline, Sainfoin, MontGuide MT 9321, Montana State University Extension Service · peer-reviewed work on condensed tannins and gastrointestinal nematodes in ruminants · producer accounts from HayTalk, quoted verbatim and attributed. Herbicide statements reflect published extension guidance; always read and follow the product label for your state. Accessed August 11, 2026.