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Tansy Flower Guide: Pest-Repelling Beauty for Your Garden

Tansy Flower on Pixabay
Botanical Name
Tanacetum vulgare
Plant Type
Flowers
Perennial Flowers
Sun Exposure
Full Sun
Part Sun
Soil pH
Varies
Bloom Time
Summer
Fall
Flower Color
Yellow
Hardiness Zone
3
4
5
6
7
8
Special Features
Attracts Bees

A charming, pest-repellent companion plant with a rich garden heritage

Samantha Johnson
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Discover tansy, a companion plant that bugs off pests and rolls out the welcome mat for helpful insects. Plus, this golden bloomer adds old-world charm to veggie patches and flower beds alike. In this guide, we’ll dig into everything you need to know about tansy: how to plant it, grow it, care for it, and put its garden superpowers to good use.

About Tansy

The stalwart tansy (Tanacetum vulgare)—also known as golden buttons, garden tansy, bitter buttons, and cow bitter—is a member of the Asteraceae family, alongside asters, sunflowers, and daisies. It stands 1 to 5 feet tall and blooms from July to September with button-like yellow flower clusters that are both fragrant and eye-catching. The upright stems are flanked by attractive, fern-like foliage.

A historic favorite, tansy is believed to have been brought to North America by the Pilgrims in 1620. Over time, this herbaceous perennial found uses beyond the garden—it was brewed into teas, used to treat various ailments, and even employed by colonists to help preserve meat.

Close-up of bee on yellow tansy flowers.
Caption: You can use tansy to attract pollinators to your garden. Credit: Nennieinszweidrei

Tansy’s Pest-Repelling Powers

Today, tansy is primarily grown as a companion plant to deter pests from nearby crops and add a touch of historic flair to modern gardens. Its essential oils are rich in compounds like thujone, camphor, and 1,8-cineole, which have demonstrated insect-repellent properties in scientific studies. 

  • Colorado Potato Beetle (Leptinotarsa decemlineata): Tansy essential oil has been shown to significantly deter feeding behavior in these beetles. Treated leaves were less likely to be eaten, suggesting potential as a natural pesticide. Source: PubMed, 2020
  • Green Peach Aphid (Myzus persicae): Allelochemicals from tansy have strong repellent effects against this aphid species, making it a useful companion for aphid-prone plants. Source: ScienceDirect
  • Fall Armyworm (Spodoptera frugiperda): When 2% tansy oil was added to artificial diets in lab tests, 73% of larvae died within 48 hours—pointing to its potential as a natural insecticide. Source: USDA CRIS Database

A Word of Caution

Tansy’s benefits come with a bold personality—it’s a vigorous spreader. It propagates through seeds, rhizomes, and even loose root fragments, which can resprout with the same DNA as the original plant (according to the University of Minnesota Extension). To keep it well-mannered in the garden:

  • Plant in containers or raised beds to contain the roots.
  • Deadhead flowers before they go to seed.
  • Monitor spreading rhizomes and dig up any wandering shoots.

With a little thoughtful maintenance, tansy can be a well-behaved—and beautiful—addition to your garden lineup.

Is Tansy Poisonous?

Yes. Tansy contains compounds (especially thujone) that can be toxic to humans and animals if consumed in large amounts. Avoid planting it near play areas or where pets roam freely. As with many herbs, a little goes a long way—and tansy is best enjoyed as a visual and aromatic asset, not a snack.

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Planting

Before planting, check if tansy (Tanacetum vulgare) is considered invasive or restricted in your state. If it’s allowed, you’ll discover it’s a hardy, low-maintenance perennial that’s easy to grow.

Tansy’s easygoing—just give it some sun (6+ hours is best) and decent drainage. It can handle dry spells and crummy soil, though it’s happiest in loamy ground.

When to Plant

  • Seeds: Sow directly outdoors after the last frost date in spring.
  • Divisions: If dividing mature plants, fall is the best time to replant the sections.

How to Plant

Like many hardy perennials from temperate climates, tansy seeds may benefit from cold stratification—a simple process of storing seeds in the fridge for 2 to 4 weeks to mimic winter conditions and encourage germination.

Before planting, consider how you want tansy to work in your garden. Some gardeners use it as a natural perimeter plant to help deter mosquitoes, flies, and even small mammals like mice.

  • Sowing Depth: Tansy seeds are tiny, so plant them shallowly—just ⅛- to ¼-inch deep. A light dusting of soil is all they need.
  • Spacing: Sow seeds about 12 inches apart, or sow densely and thin the seedlings as they emerge.
  • Watering: Keep the soil moist (but not soggy) until seedlings are established. Once grown, tansy is quite drought tolerant.

Growing

Tansy spreads through below-surface rhizomes and also by seed.

  • Tansy is primarily a full-sun flower, but it can tolerate some shade, giving you more flexibility in placement.
  • Tansy is tough, and fairly drought resistant when mature, so you definitely don’t want to overwater.
  • Fertile, well-draining soil is a great start, but soil type really can vary as tansy isn’t picky (which is part of why it can be invasive at times!).
  • It’s hardy in Zones 3 to 8, but because it requires cold stratification, it may struggle to propagate in warmer regions.
  • Honey bees love tansy, so growing it can bring in the pollinators while discouraging “bad” bugs.
  • As with so many “wildflowers,” tansy is quite self-sufficient and probably won’t need fertilizing or soil amendments.
  • To prevent tansy from spreading where you don’t want it, plan on controlling the area around your tansy by mowing or a similar method.
  • Soil pH isn’t terribly important; tansy can handle a range from approximately 5.0 to 7.5.
  • The fern-like leaves of tansy add interest and texture to the garden.
  • To help keep spreading under control, plan on removing flowers before they go to seed.
  • Tansy dries beautifully and makes a great flower for this purpose.
  • It also makes an excellent companion plant, helping to act as a natural insect repellent to protect plants nearby.
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Pests/Diseases

Because of its natural hardiness and bug-repelling nature, Tansy has few foes in the world. Aphids may try to forge an offense, but it’s usually not a real problem and they can often be dispatched with a hose. But speaking of hoses—too much moisture is probably your tansy’s biggest threat. It can lead to fungal issues on and around the plant and disrupt its preference for dry soil.

Wit and Wisdom

  • In ancient Greek mythology, the shepherd Ganymede used tansy as a magic potion to live forever. According to the North Carolina State Extension, the Greek word athanasia means “immortal” and is related to the name of the plant.
  • In past times, tansy was used as a bit of a good-luck charm, even placed above barn doorways in a manner somewhat similar to a horseshoe. Of course, tansy’s fly-repellent properties may have been the real reason!
  • Exodus 12:8 in the Bible mentions meal preparation: “…with bitter herbs they shall eat it.” The “bitter herbs” could easily have contained tansy among others.
  • While tansy isn’t recommended for human use today because of its high toxicity, in centuries past it was utilized in various folk remedies as a deworming agent.
  • Some say the Pilgrims brought tansy to the New World.
  • Tansy is native to Europe and Asia, but has naturalized, so you’ll find it across North America in ditches, along roadsides and pastures.
Flowering tansy plant growing wild in pastures.
You’ll often find tansy patches in pastures and fields and along roadsides and ditches. Credit: Arcaion
Flowers
About The Author

Samantha Johnson

Samantha Johnson is an award-winning author and gardening expert with over 20 years of experience cultivating heirloom vegetables and sharing her passion for rural living. Read More from Samantha Johnson
 

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