Tansy: What It Looks Like, Where It Grows, Growing in a Bed and a Toxicity Warning

In brief: Tansy (Tanacetum vulgare) is a tall aromatic perennial with yellow button-like flowers in dense corymbs from July to September. It grows in sun and in well-drained soil and spreads easily by rhizomes. It is not used internally and is poisonous, so grow it only as an ornamental plant out of reach of children and animals.

Tansy is a plant you know from the edges of paths, waste ground and non-agricultural land. Its yellow button-like flowers shine in summer on tall stems, and the leaves smell strongly when crushed. In the garden it is valued by those looking for an undemanding natural perennial or material for dried arrangements.

But be careful: tansy is considered poisonous. This article therefore concentrates on garden growing and safety. We do not describe any health use.

What tansy looks like

From a distance tansy looks like an unmissable yellow screen. The inflorescence is dense and stays in flower for a long time.

Where tansy grows and what it needs

In the wild it grows on the edges of paths, field margins, waste ground and unpaved areas. It likes sun and well-drained soil. It tolerates drought and poor soil. In the garden a sunny position suits it, where it does not matter that it spreads. It is not suitable for shade or damp places.

Sowing and propagation

Tansy is propagated by seeds and by division. The seeds are tiny and need light to germinate, so do not cover them, just press them in. They are sown in spring into trays or outdoors in autumn.

1. Prepare a well-drained seed substrate and level the surface.
2. Scatter the seeds thinly on the surface and press them in.
3. Keep moderate moisture and light; germination takes several weeks.
4. After hardening off, plant the seedlings outdoors, preferably in spring, at a spacing of 50–60 cm.

Beware of spreading

Tansy spreads by underground rhizomes and seeds. Within a few years it forms dense clumps that expand into the surroundings. If you do not want it to take over the bed, restrict it with a root barrier sunk to a depth of 30–40 cm, or grow it in a separate large container. Cut off the spent flower heads before the seeds ripen. Remove the remains of rhizomes if you are removing the plant. Do not put garden waste with rhizomes into a home compost heap.

How to remove tansy if it has spread too much

1. In autumn or spring dig up the whole clump with its rhizomes with a spade or digging fork.
2. Sift the soil and pick out even tiny pieces of rhizome.
3. Do not put the removed plants and rhizomes in compost, but in bio-waste or sealed waste.
4. For the rest of the season remove every new shoot as soon as it appears.
5. Cover the area with mulching fabric or a layer of cardboard if you want to starve the plant out.

It usually takes one to two years of consistent work before the plant is removed completely. If you do not want to give up on it, transplant it into a large container or to a place where it will not matter.

Care during the year

Tansy is undemanding. Water only after planting and during long drought. Feeding is not needed. You can support the tall stems. After flowering cut the plant back or leave the stems over winter for insects. In spring remove old stems just above the ground.

Dried flowers and decorations

Tansy flowers last a long time after drying and are suitable for dried arrangements. Cut the stems when the flowers are fully open, tie them into small bunches and hang them upside down in a ventilated place in the shade. After drying the golden colour is well preserved. Wear gloves when handling it; the plant may irritate the skin of sensitive people.

Tansy and insects in the garden

Insects visit the yellow flowers, mainly at a time when other plants are already finishing flowering. The scent of the leaves is strong and some growers plant the plant at the edge of the garden. An effect against pests cannot be reliably promised; we take it as growers' experience. If you need to protect plants from pests, use proven and registered methods.

Care plan through the year

Most common mistakes

• Planting in the middle of a bed. The plant crowds out its neighbours and is hard to remove.
• Leaving the seeds. Self-seeding overruns the garden.
• Use in the kitchen or as tea. The plant is poisonous.
• Planting by a children's playground. Children may taste or touch the plants.
• Careless handling without gloves. It can irritate the skin.

Tansy and similar plants

Tansy is often mistaken for chamomile or ox-eye daisy because of the look of the flowers, but it differs mainly in shape: it has no white ray florets, only yellow buttons. It is also considerably taller and has a stronger scent. Be careful when identifying plants collected in the wild; species of the carrot family and the daisy family are easily mixed up. Never use a plant whose species you do not know for certain.

Warning: toxicity

• Tansy is poisonous; do not use it internally, not even as tea, and do not add it to food or drinks.
• We do not recommend home infusions, tinctures and oils.
• Keep it out of the reach of children and pets; do not plant it where they could nibble it.
• Wear gloves when working with the plant. In sensitive people it may cause skin irritation.
• Avoid plants of this kind during pregnancy and breastfeeding.

If you have doubts about the identification of the species or about the safety of growing it in your garden, ask in the advice service and do not forget to add a photograph of the whole plant including flowers and leaves. It will help a faster and more precise answer. Always choose caution.

Frequently asked questions

What is tansy?

An aromatic tall perennial with yellow button-like flowers that grows on waste ground and path edges.

When does tansy flower?

From July to September.

How should tansy be sown?

In spring into trays or in autumn outdoors, seeds on the surface and not covered.

How can its spread be limited?

With a root barrier, growing in a container, cutting off the flower heads before the seeds ripen and regularly removing shoots outside the designated place.

Is tansy poisonous?

Yes, it is considered poisonous. Do not use it internally and keep it away from children and animals.

Sources

• Tansy – a poisonous and medicinal herb of the daisy family, Wikipedia
• Daisy family – the largest family of dicotyledonous plants, Wikipedia

Updated: 5 October 2026