Potential killers lurk in garden

DEADLY SEEDS: The castor oil plant Ricinus communis.
DEADLY SEEDS: The castor oil plant Ricinus communis.

I admit, even though it's the first week of daylight saving and we should've turned the telly off for summer, we sat down on Monday night to be part of the global audience watching the critically acclaimed Homeland series.

If you've missed the hype, it's an American TV thriller-drama about a United States marine who, after he was held captive by al Qaeda in Iran for eight years, has returned home with political aspirations for the vice presidency.

However, he's suspected by one CIA agent (the female lead) to have been “turned” by his captors and, she maintains, is now a threat to his homeland. It's gripping, edgy, now stuff, made just weeks before its release last Monday simultaneously to US and overseas audiences, including New Zealand.

And what's this got to do with the garden, you ask? Well, inspired by the spy thriller stuff and seeking more escapism on Tuesday night, after a big day in the garden, we watched an old DVD of the original Tinker, Tailor, Soldier, Spy series, starring the legendary Alec Guinness.

And that reminded me how far we've come from the cold war days when a Bulgarian dissident, Georgi Markov, was assassinated in London in 1978 with poison fired from an umbrella as he walked across Waterloo Bridge. Shortly after Georgi felt a mysterious, sharp jab and saw a man picking up an umbrella, he developed a high temperature and died in hospital four days later.

Talk about a gripping, but real-life, thriller drama. A government-assisted autopsy found Georgi had been killed by a tiny pellet containing ricin, the deadly toxin from the castor oil plant, Ricinus communis, a common garden escape found around Nelson. It was only detected in Georgi because the pellet containing the poison had not dissolved, as was probably anticipated in the murder plot.

The Scotland Yard investigation following his death revealed a convoluted maize of international cold war intelligence and intrigue between the Soviet KGB and Bulgarian secret police, all of which seems so incredibly last century these days.

But poisonous plants are very much this century and, for those unaware, a potential killer. Which was why a friend of mine with young children was alarmed when she found out that hellebores are poisonous.

Her initial reaction was to get rid of them, an understandable response for a mother wanting to protect her children and ensure their garden play area was safe. But then, as I quickly pointed out she'd have to dig out half the garden if she wanted to get rid of all the poisonous plants.

Rather than simply be aware of the toxicity of individual plants, because there are so many in the home garden, for peace of mind and reality, it's important to understand also the risk of poisoning.

Now, I want to say at the outset I'm not advocating a totally laissez-faire approach here, with the cliched argument that gardening is safer than driving the roads, but simply contexturalising the risk of poisoning from plants. Hellebores and castor oil plants are two good examples of why poisoning is about risk, not just toxicity.

Just how many of you recognise castor oil plants and can think of places you know around Nelson where its growing? Even if you knew it was poisonous, did you know just how poisonous?

It took just 0.2 milligrams of the ricin (the concentrated toxin extracted from the seed of the castor oil plant) to kill poor Georgi. And, checking my definitive bookshelf reference, Poisonous Plants of New Zealand by Henry Connor, he says, ingesting as few as two to four castor beans (seeds) “could prove fatal”.

In other words, this is not a plant to mess around with, yet I and probably most of you have stumbled on it countless times all around Nelson city and the region, growing wild in readily accessible places as well as many home gardens. It's a plant of great colour (deep burgundy) and distinctive form, that grows up particularly fast in the summer and makes a dramatic statement in the garden.

It's also the plant that, amazingly, produces the non-toxic tonic, castor oil, also extracted from the seeds, such is the complex chemical constitution of the plant.

But, given Ricinus toxicity and prevalence, how many poisonings are you aware of? Probably none. Although there have been sublethal poisonings reported in this country, and stock are very susceptible to it, we can all name many more prevalent killers.

The issue around risk is how likely it is for a child who does not understand the potential poisoning to eat such a seed or bean. If you think about what attracts children to plants, it's likely to be things that look like food, brightly coloured berries that look or smell like lollies or favourite fruit rather than dull, brown or purple beans.

Most kids, of course, hate beans, a real, rather than imagined excuse, where many beans contain substances young stomachs are unable to digest so cause the typical “tummy ache” parents can be so intolerant of. But, obviously there are also lots of times when children will simply put anything they can hold in their mouth which, if it were castor oil seeds, could prove fatal.

The lesson here is that, if you or a child were to ingest the seeds (or in fact the leaves which, although poisonous are far less so than the seeds) or be close enough to the plant to be susceptible to the inhaled allergenic effect (causing irritation of the eyes, nose, throat also nausea and vomiting), it can kill, but largely goes unnoticed in society.

As does the fact that, in addition to hellebores, lots of other common everyday plants are also poisonous if eaten and sometimes if they are just touched (primulas and native nettle) or inhaled (including smoke from burning oleander).

Many of them are probably right under your nose, flowering in your garden right now such as daphne, kowhai and daffodils as well as hellebores and iceland poppies.

Children are hardly likely to eat a daffodil bulb or daphne leaves or poppy flowers. But they might like to try a bright orange Arum lily seed in summer.

The key is how attractive are they to your children, whether they are likely to taste or touch plants. Rather than how poisonous the plants are, it's the risk they present that you need to consider.

Rather than annihilate your garden, the answer to minimising risk is to be informed. Check out the list of culprits lurking in your garden that are of likely risk to children. It is from a document, Plants in New Zealand Poisonous to Children, on the Landcare Research website at landcareresearch.co.nz.

Key points about poisonous plants around children include: Advise children not to eat plants and especially new plant material unless guided by an adult.

Children should be under adult supervision when near or around plants that could cause skin irritation (rhus, nettle).

Not all bitter plants are poisonous nor do all poisonous plants taste bitter so taste can not be relied on as an indication of toxicity.

In the event of suspected poisoning, try to establish which plant was eaten, ingested and take a piece with you when going for medical help.

If a poisoning occurs, call the 24-hour phone line on 0800 POISON or 0800 764 766.

Some common poisonous plants out now: Daphne, daffodil, wisteria, helleborus, stinking iris (Iris foetidissma), lily of the valley, iceland poppy, kowhai and, to touch, primula, parsnips and rhus.

Others that are in flower later in the season include oleander, ngaio, poro poro, poinsettia, delphiniums, datura, cestrums, arum lily and castor oil plants, plus weeds such as boxthorn, hemlock, nightshades and celery-leaved buttercup.


Now that October has arrived, it's time to get serious about planting the summer vege garden.

Get growing with your kids these holidays and sow sunflowers together for the summer garden.

Have fun times together making sand saucers using spring flowers.

Sow your cucurbits (zucchini, pumpkins, cucumbers and squash) indoors now so they are ready to plant out at or after Labour Weekend.

Prepare the space to plant aubergines, peppers, tomatoes and chillies at Labour Weekend but keep your seedlings inside under protection until then.

Rhododendrons are gross feeders and need fertilising now with either proprietary fertiliser or bulky organic manure (such as sheepy "do") as they finish flowering to boost the new shoot growth.

Plant delphiniums, foxgloves, larkspur, hollyhocks and Canterbury bells now for height in the summer garden.

Keep planting spring salad greens, radish and onions for ongoing cropping.

Feed spring flowering bulbs (daffodils) after flowering to boost bulb growth and next year's flower buds.