Poisonous plants in your garden

Maxine Farmer looks at the potentially harmful plants we unwittingly bring into our gardens.
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Several years ago, I had two ‘gardeners’ helping me during the main growing season. They were very willing but had no horticultural training, something that was really brought home to me when they asked me the name of the plant with the berries and pretty little purple flowers. I duly followed them to the said plant, which was belladonna (deadly nightshade or woody nightshade). As they were both mothers of small children, I was really alarmed at this lack of knowledge. Needless to say, I didn’t continue with that working relationship the following year.

In fact, quite a few plants in the garden are either poisonous or potentially harmful in one way or another.  According to Kew Gardens, children under the age of five are particularly vulnerable, presumably. While it is difficult for any of us – whether amateur or professional gardener – to have an encyclopaedic knowledge of what’s OK and what’s not, it does make sense to be aware of some of the biggest dangers.

Most of us probably know that nightshade and digitalis (the common foxglove) are highly poisonous and can even be fatal. But here are a few other examples of which you may not be aware:



Aconitum – or Monkshood, this is a statuesque late summer flowering perennial, with beautiful flowers usually in shades of blue.  It is extremely poisonous and therefore, plant with care at the back of the border or, if you have small children, not at all.

Delphiniums – all parts of these popular cottage garden favourites are potentially fatal if ingested.
Colchicum (autumn crocus) – another one that appears on the fatality risk list.

Euphorbias and hellebores – both these plant families have become increasingly popular in recent years and deservedly so because of their architectural foliage. However, always wear gloves when handling them, particularly if you are planning to cut the stems, because the milky sap can be extremely irritating to bare skin.

Giant hog weed – this common weed seems to be more widespread this year and it comes with a big health warning. The toxins in the sap can react to sunlight and cause severe blistering and even scarring. Do not attempt to deal with it yourself, seek professional assistance. It is a successful self-seeder and quite hard to eradicate, even using powerful systemic weedkillers, so don’t let it become a problem and if you recognise it in your neighbour’s garden, tell them!

Laburnum tree

Laburnum tree

Laburnum, daphne, cytisis (Broom) – all of these common shrubs are potentially fatal if ingested.
Lantana – a houseplant that is also being used in summer bedding schemes is highly poisonous.
These are just a few examples and there are many more. There are also numerous plants that are dangerous to dogs and cats, not just humans.

So what should we all be doing? Should we all be avoiding them altogether? That choice is yours. Personally, I still plant some of the perennials and shrubs listed above, though with some caution. If I had small children in the garden on a regular basis – particularly unsupervised – I would probably consider removing those plants altogether.

Tips for handling poisonous plants:

  1. Check the label – when buying, have a look at the plant label in the garden centre for any warnings
  2. Wash hands thoroughly – which should be common practice anyway, but always ensure that hands are cleaned after a session in the garden and wear good gloves
  3. Create boundaries – plants aren’t dangerous to children and pets if they can’t reach them
  4. Get some knowledge – Kew Gardens has an excellent book called ‘Poisonous Plants’ by Elizabeth A Dauncey, available from Amazon and other sources
  5. Get online – Also, if you have pets, type ‘plants that are poisonous to cats/dogs’ into Google or your preferred search engine and you will see a number of lists that you can check against.

Finally, if in doubt, assume that a plant is dangerous. Gardens are beautiful places but we need to remember that Mother Nature is not a Disney fairyland and that we need to respect that.

Last modified: December 31, 2020

Written by 2:11 pm Gardening