Wednesday, August 05, 2009

A week in Northumberland #3: Poisonous plants

Perhaps the most talked-about bit of an already very talked-about garden is Alnwick Garden's Poison Garden. You're only allowed inside the locked gates with a guide, no doubt mainly because of those pesky health and safety types but in fact a handy way of emphasising just how dangerous these plants can be.

Here you'll find plants in cages. A cannabis plant grown with a special Defra license and a (admittedly a little weedy-looking and therefore not very scary) Datura or two are among the prison population.

There are also a lot of very familiar plants, and as someone who likes to think they know their plants well enough to be pretty sure which ones to avoid, it was distinctly unsettling to learn that ivy, box, and laurel are among the harmful plants with a place in this garden.

So - if you spot any of this motley crew lurking in your beds and borders, or indeed in the hedgerows and fields: be afraid... be very afraid...

Hemlock is a member of the parsley family and looks alarmingly similar to cow parsley in the wild - but it smells like mice and has bright pink stems

Hemlock (Conium maculatum): Probably the most famous poisonous plant of them all, and still found commonly in the countryside. When Socrates used it to commit suicide I don't suppose anyone mentioned to him that it paralyses you from the feet upwards. So you're entirely conscious while it numbs first your legs, then your torso, and finally stops your lungs from working so you suffocate. Meanwhile the brain is entirely unaffected, and remains lucid throughout. Mmm. Nice.

Ivy (Hedera spp): Ever noticed when you're pruning a big mass of ivy that you start coughing? That's not just because it's dusty under there because it's the first time you've clipped it back for centuries. You're breathing in saponins, which in quantity can lead to laboured breathing, convulsions and eventually coma. So next time, wear a face mask.

Box (Buxus sempervirens): If you're clipping box hedges, don't wander off and have a cup of tea before you pick up all the little bits that have dropped on the ground. As they dry, they release buxine, and if you touch it, it'll give you an irritating skin rash.

Even boring old laurel can bite

Daffodils (Narcissus spp): People eat daffodils thinking they're onions. No, really - it's true. Unfortunately the law of natural selection doesn't apply here: though eating as little as half a bulb gives a nasty stomach complaint, it won't rid the world of someone with a criminal lack of common sense.

Laurel (Prunus laurocerasus): Now this one came as a complete surprise. If you stack all your prunings in a big bag and stuff them in the back of the car, then think, "oh sod it, I can't be bothered to go to the tip today" you will pay for your laziness with a car full of cyanide fumes in the morning. Apparently entomologists kill bugs by putting them in a jar with crushed laurel leaves. Much the same principle, really.

Autumn crocus (Colchicum autumnale): Crikey, you don't want to be mistaking this one for onions. In fact most people don't: they mistake it for wild garlic, which it greatly resembles (a lot more than daffodils resemble onions, I suspect). Symptoms sound like something out of a particularly gruesome episode of Casualty: convulsions, cardiovascular collapse and multiple organ failure. Apparently it's a lot like dying of cholera.

Rue is deadly - though the bees don't seem to mind

Rue (Ruta graveolens): Ever heard of the phrase, "Rue the day"? As in, "I rue the day I ever planted this damn thing in my herb garden?" Well though this is a very pretty plant, and found in lots of people's herb gardens, it's really quite a vicious little thing. Brushing against it, especially on a sunny day, can blister skin to the point of burns: what's really extraordinary though is that rue is often recommended (and grown in people's herb gardens) for rubbing onto the skin as a mosquito repellent. Please don't do this: mosquito bites will seem as the kiss of angels in comparison. Eating it causes acute gastroenteritis and eventually liver failure, though fortunately it tastes disgusting.

I've left out the obvious poisonous plants we all (hopefully) know about: the monkshoods, cuckoo pints and nettles which all gardeners should handle with care. But there are a whole lot more - aquilegias, cimicifuga, periwinkles, snowdrops and daphnes to name but a few - which I could have included and which you should know about.

I'm indebted to John Robertson, a former guide at Alnwick's Poison Garden, for supplementing my patchy recollections with extra information: and if you want to know about the bits I've left out, I can only direct you to his exceptionally good website where all these plants and more are described in gruesome detail.


Julia said...

That's fascinating - Hubster is into medicinal herbs, so he'll probably love all this (he said "I'd like to know more about poisons" - which has made me suspicious every time he makes a cup of tea for me). And we're due a visit to Durham to see my brother anyway so we can persuade them to do a day trip.

VP said...

The poison garden opened the year after we went there and I thought we hadn't really missed anything. You've changed my mind.

In my research re public planting I've come across one local authority which specifies 'no poisonous plants' when inviting companies to tender for their municipal schemes. It's accompanied by a terrifyingly long list of what's on their banned list. I'm wondering if a lot more authorities have exactly the same stipulation, seeing that about 4 plants seem to make up a lot of schemes I've seen.

nonicky said...

Thanks for the mention, that's very kind.

I was interested in your reference to the 'weedy' daturas. I was in the garden, purely as a visitor these days, a couple of weeks ago and was told that there has been a problem this year and they don't know what it is. They think it might be the top dressing they used last year and, I was told, they are having some tests done.

I was really quite sad to see how small and poorly many of the plants looked.

They even had a very ungiant giant hogweed.

thepoisongarden said...


Hopefully fixed the 'nonicky' problem.

Incidentally, I'm surprised you didn't mention the ricinus communis, castor oil plant. That should be one of the most stunning plants at this time of year; I know mine are looking very dramatic. I hope that's not another victim of the soil problem.

jonathannex said...
This comment has been removed by the author.
The Constant Gardener said...

Hello John, good to hear from you! Yes I remember they mentioned they were having problems with their daturas. Didn't spot the miniature giant hogweed though - that would have been worth looking out for!!

The Ricinus was fine, and very pretty: I didn't mention it simply because it came under the heading of "plants gardeners ought to know are poisonous" for me - and I had to leave out such a lot from the garden it was a tricky call. I'm growing Ricinus in my own garden at the moment and it's looking truly gorgeous just now - the colours are amazing. Just hope the kids don't think it looks tasty...

thepoisongarden said...

Actually, it's not the first time I've seen a mini Heracleum mantegazzianum. In 2006, the gardeners planted three in the 2m high cage and, by early summer, it looked as though they were going to burst out. Wearing protective clothing four gardeners lifted the cage off and two cut the plants down to ground level. Within a few weeks they'd regrown to about a metre high and flowered. The flowers were removed to prevent them setting seed and within a further few weeks one of the plants had flowered at about a foot high.

It was an amazing indication of a plant's determination to reproduce.

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