Why You Should (and Shouldn't) Grow Tansy

9 July 2020, written by Ann Marie Hendry

Just when you think you can’t fall hopelessly in love with another flower, along struts tansy, and the fireworks go off again. Its ferny foliage captivates, its scent allures, and its quirky button-shaped flowers enchant. But only fools rush in, especially when they’ve been burned by unsuitable floral beaus before – I’m thinking of that aggressive mint, the over-ardent aquilegia, and the rambunctious periwinkle that I’ve dallied with in the past.

So, with plenty of painful experience to rein me in, I’m approaching a romance with tansy with utmost caution. There are few things more heartbreaking than ripping the roots of an adored plant from the soil (and having to do it over and over again for weeks, months, years…possibly forever) because it loves your garden a little too much.

Reasons Not to Grow Tansy in Your Garden

When you’re first getting to know a handsome stranger it’s tempting to only notice his good points, but if you’re planning on entering into a long-term relationship it’s worth being realistic. Everyone has their dark side!

And tansy’s dark side is darker than most – it’s literally a killer. Despite historically being commonly used as a flavouring, bitter-tasting tansy contains a toxic essential oil that can cause liver and brain damage and even kill humans and other animals. On a less lethal level, it can also prompt an allergic reaction in some individuals when touching the leaves.

If that wasn’t enough to set the alarm bells ringing, tansy is also the type to make itself at home in your garden – a little too well! It both reseeds readily and spreads by underground rhizomes, so a flirtation with a few tansy plants could soon turn into a more permanent arrangement than you originally envisaged. In some parts of North America tansy is so invasive it’s actually listed as a noxious weed and is not permitted.

“Invasive — Approach growing tansy with care because it may become invasive

And Now Some Great Reasons to Grow Tansy

OK, so tansy isn’t perfect, but who is? A few flaws could almost be considered endearing…couldn’t they? All right, I admit – poisoning people to death is a pretty major flaw. So it’s got to have more to back it up than just a pretty golden face.

Fortunately, it does. That garden-grabbing nature means it’s happy in most soils and it doesn’t need feeding, so even those of us who are less than nurturing in our plant relationships can rest assured that we won’t ever neglect our beloved. Tansy can tolerate a little shade, making it useful for filling space in those less-loved parts of the garden, and once established it can cope with drought too. It will even help improve the soil because it accumulates potassium.

Tansy is also a staunch garden protector. There are impressive claims that it repels all kinds of pests such as ants, flies, fleas, moths, mosquitoes, ticks, and even mice. Yeah, yeah – I’ve heard that old line before! But the toxic nature of the essential oils in its leaves mean it can be used to make an insecticide, so perhaps there’s some truth in it. The strong-smelling flowers and leaves can be dried and gathered in a bouquet or used as part of a pot-pourri mix to keep bugs out of your house.

“Growing — Growing tansy in a container can prevent it from taking over your garden

You’ll need to compete with some bugs for tansy’s affections though. Honeybees in particular find it irresistible, and ladybirds hold it in such high esteem they will seek out tansy to lay their eggs on. Tansy will host other pest predators such as braconid wasps and minute pirate bugs too.

While larger quantities can result in tansy poisoning, it’s said that small amounts of the leaves and flowers are fine to eat and can be used in omelettes, stews, salads and more. Personally, I think I’ll play it safe and pass on that one. You have to keep some mystery in any relationship.

So, I’m taking it slow with tansy. My plant is growing in a container where I can admire it but where it can’t move into my garden in a til-death-us-do-part kind of way. I’ve also planted feverfew, lupins, foxgloves and asters, because there’s no need to settle down with the first handsome flower that catches the eye. It’s still early days, but you know what? I think this one might be a keeper.