6 Best Tansy Seeds For Controlling Flies Around Livestock Old-Timers Swear By

You’ve seen it a hundred times. A hot, still August afternoon, and the flies are driving your goats, sheep, or cattle absolutely mad. You can spray and trap all you want, but the swarm just seems to come back stronger. This is where old-timer wisdom comes in, using tough, reliable plants to create a living barrier that insects simply hate.

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Why Old-Timers Plant Tansy for Fly Control

Before chemical fly sprays were on every feed store shelf, farmers used what they had. Tansy (Tanacetum vulgare) was a staple because it’s aggressive, perennial, and packs a punch that flies, ants, and mosquitoes can’t stand. The plant is loaded with compounds like thujone, giving it a sharp, camphor-like scent that acts as a powerful natural insect repellent.

The strategy was simple: plant a dense hedge of it where flies congregate. Think along the outside of a barn wall, around the manure pile, or on the far side of a pasture fence. The aromatic oils get carried on the breeze, creating a no-fly zone. It’s a set-it-and-forget-it solution that comes back year after year, which is exactly what a busy farmer needs.

But here’s the critical part they always knew: tansy is toxic to most livestock if ingested in quantity. It was never planted as forage. It’s a tool, and like any tool, you have to use it correctly. The goal is to create an aromatic barrier your animals can’t reach, not a snack bar.

True Leaf Market Common Tansy: The Classic

When you think of tansy, this is it. True Leaf Market’s Common Tansy seed gives you the classic, no-frills plant that has been used for centuries. It grows vigorously, reaching three to four feet tall with stiff, woody stems and the iconic clusters of bright yellow, button-like flowers. Its foliage is dark green and fern-like, and the scent is unmistakably potent.

This is your workhorse variety. It’s not fancy, but it is incredibly effective for creating a dense, functional hedge. Plant this where you need maximum impact and aren’t concerned with delicate aesthetics. It’s perfect for establishing a thick border along a property line or creating a full-circle barrier around your compost or manure heap to keep fly populations from ever taking hold.

Because it’s the standard species, its growth habit is predictable and aggressive. It spreads by rhizomes, so it will fill in an area quickly, choking out weeds and forming the solid wall of scent you’re looking for. If you just want what has always worked, this is the seed to start with.

‘Isla Gold’ Tansy: A Colorful Fly Deterrent

Not all tansy has to look purely utilitarian. The ‘Isla Gold’ variety (Tanacetum vulgare ‘Isla Gold’) offers the same fly-repelling properties but with a major aesthetic upgrade. Its foliage is a brilliant chartreuse-gold, especially in full sun. This makes it a dual-purpose plant: it deters pests while also adding a splash of bright color to your landscape.

The tradeoff for its beauty is slightly less aggressive growth compared to its wilder cousin. It still forms a nice clump and produces the same yellow button flowers, but it’s a bit more "tame" and less likely to take over the world. This makes it an excellent choice for planting near the farmhouse, in a dedicated herb garden, or along a walkway where you want both function and form.

Think of ‘Isla Gold’ as the tansy you can plant in plain sight. It provides a beautiful, lacy-textured backdrop for other flowers while quietly doing its job of keeping flies away from your porch or outdoor work areas. You get the benefits without the sometimes-weedy look of common tansy.

Fernleaf ‘Crispum’ Tansy for Dense Borders

The Fernleaf or ‘Crispum’ variety (Tanacetum vulgare ‘Crispum’) is all about texture. Its leaves are distinctly different from common tansy—they are crinkled, curled, and almost look like parsley or decorative kale. This unique foliage has a very practical advantage for fly control.

Because the leaves are so densely packed and ruffled, a hedge of ‘Crispum’ tansy creates an incredibly thick visual and aromatic barrier. Air moves through it more slowly, holding that repellent scent in place more effectively. It tends to be a bit more compact and shorter than common tansy, making it ideal for a neat, solid border that won’t get leggy or fall over.

This is the variety to choose if your goal is a tidy, impenetrable hedge. Plant it along the outside of a chicken run or as a low border around a barn foundation. Its dense growth habit means fewer gaps for flies to slip through and a more concentrated wall of scent right where you need it.

Eden Brothers Wild Tansy for Naturalizing

Sometimes you don’t want a tidy hedge. Sometimes you have a back corner of the property, a ditch, or a long, rough fenceline that needs a tough, self-sufficient plant to take over. That’s where a wild-type tansy, like the one from Eden Brothers, shines. This seed is meant for naturalizing.

This variety is selected for vigor and resilience. It’s designed to be sown in an area where it can spread and establish a large, permanent colony with minimal intervention. It will outcompete weeds and thrive in less-than-ideal soil, making it perfect for those trouble spots on the farm. The goal here isn’t a manicured look; it’s a massive, fly-repelling patch.

Be deliberate with this one. Its strength is its ability to spread, which can also be its downside if planted in the wrong spot. Use it in a designated "wild" area where its rhizomatous nature is a feature, not a bug. Let it fill in that 100-foot stretch along the woods, and you’ll create a powerful buffer zone for your entire property.

Baker Creek’s Heirloom Tansy for Potency

Heirloom seeds are bred for traits that matter, not just for commercial uniformity. With a plant like tansy, that often means potency. An heirloom variety from a reputable source like Baker Creek is likely to have been selected over generations for a strong, pungent aroma—the very thing that makes it effective against flies.

While all tansy works, this is the choice for the farmer who wants to maximize the repellent quality. The focus of this strain isn’t on a unique leaf shape or color, but on preserving the powerful, camphor-heavy scent profile of the original plant. It’s about function over everything else.

Plant this variety when your primary, single-minded goal is to drive flies away. The visual appeal is secondary. This is the seed you use to ring the manure pile or plant downwind from your barn. It’s a pure, unadulterated tool chosen for its raw effectiveness.

Mountain Valley Tansy: High-Altitude Hardy

Not everyone farms on flat, fertile land in a moderate climate. If you’re in the mountains or a northern region with cold winters and rocky soil, you need plants that can handle it. Sourcing tansy from a grower that understands these conditions, like Mountain Valley, ensures you get a strain that is genetically predisposed to thrive.

Tansy is naturally hardy, but a strain adapted to high-altitude or cold-climate growing will have an edge. It will emerge more reliably after a harsh winter and establish itself more quickly in challenging soil. This resilience is key, as a weak, struggling plant won’t produce the lush growth needed for an effective aromatic barrier.

Choosing a regionally-adapted seed is just smart farming. It saves you the time and frustration of trying to coddle a plant that isn’t suited for your environment. For those in tough climates, this is the most reliable path to establishing a healthy, permanent tansy patch.

Planting Tansy Safely Around Your Livestock

This cannot be stressed enough: Tansy is toxic if eaten by cattle, horses, goats, and other livestock. The same compounds that repel flies can cause serious harm if consumed. Using it effectively means using it safely, which is entirely achievable with smart placement.

The number one rule is to plant tansy where animals have zero access. It should always be on the outside of a fence, never within the pasture. For extra security, create a buffer zone. A three-to-four-foot mowed strip between the fenceline and the tansy hedge ensures an animal can’t just stick its head through to graze on it.

Your best locations are areas animals can’t reach anyway.

• Around the foundation of the barn or outbuildings.
• In a dedicated, fenced-off herb garden.
• Encircling the manure or compost pile.
• Along the road-facing side of a perimeter fence.

Remember that tansy spreads by underground rhizomes. If planting right against a woven wire fence, consider burying a root barrier 12 inches deep to keep it from sending shoots into the pasture. The goal is for the scent to drift over the animals, not for the plant to get into their mouths.

Choosing the right tansy seed comes down to matching the plant’s specific traits to your farm’s needs. Whether you need the ornamental beauty of ‘Isla Gold’ by the house or the raw power of an heirloom variety by the barn, there’s a tansy that fits. Just remember to plant it thoughtfully, always putting the safety of your animals first.