Why do you need to know if your plant is harmful?

I was recently asked to visit the Poison Garden in Alnwick, for ITV’s This Morning. A new exhibit was being added to the garden. Whilst reporting on the flora in the garden along with the new arrival (Gympie-Gympie Plant), I started to think about what plants we have in our own gardens.

This lead me to come up with a list of 12 plants detailed here that are wonderful additions to any garden space. They are beautiful, add structure and colour, and have been enjoyed for many years.

And they also are either capable of stinging you or are poisonous if ingested. You should not fear them. But it is always worth being aware of what you have in your garden.

If you have pets or young children who may want to nibble on the first thing they find, it is always safer to be aware of what might be accessible to them.

Also, these plants pose no threat if they are enjoyed visually.

David Domoney at the Poison Garden in Alnwick

If you are unsure of what plant you have, or whether it may be harmful to you or your loved ones, there are ways to be sure. Take it, or a photo of it, into your local garden centre. There are well-informed gardeners working away there who will be more than happy to help you out.

To stay on the safe side if you have some particularly snack-happy pets or children, avoid these plants, or plant them somewhere out of reach. However, if you have these plants, make sure children and pets are accompanied when outside, and sweep up any plant debris like petals or leaves.

1 – Digitalis purpurea (Foxglove)

Digitalis purpurea (Foxglove)


These wonderful flowers produce a beautiful display in the garden and are loved by pollinators, particularly bees. As a beekeeper myself, I am always keen to keep pollinator plants like Foxgloves in my garden.

They grow very tall, which is a brilliant way to add colourful height to your garden borders.

Potential harm

All parts of the foxglove are poisonous. The flowers contain a compound used for treating heart failure and are the source of the heart drug digoxin.

Symptoms of Foxglove poisoning include nausea, headache, skin irritation, and diarrhoea.

Containing cardiac glycosides, it can lead to heart and kidney problems. Recorded Foxglove poisonings are very rare in the UK.

2 – Taxus baccata (English Yew)



Yew trees are commonly found in gardens in the UK. And it is often grown ornamentally as trees or clipped hedges or topiary.

They are some of the oldest living species of tree in Europe. Surprisingly, some are even thought to be over 2000 years old!

Dating Yew trees is quite difficult, however, as they hollow out with time so their rings can’t be counted.

Potential harm

This tree could kill Yew! Most parts, especially the seeds, are highly toxic by ingestion and can lead to rapid death, often without previous symptoms.

The fleshy fruit of the berry is not poisonous and often enjoyed by birds. However, the seed at the centre are highly poisonous and could kill very quickly.

3 – Brugmansia (Angel’s Trumpet)

Brugmansia angel's trumpet


This tender shrub produces fantastic trumpet-shaped flowers that have a wonderful fragrance.

Thanks to the hanging nature of the blooms, I consider this gorgeous and ethereal plant perfect for containers.

Potential harm

All parts of this plant are highly toxic if ingested, with the seeds being especially dangerous.

In addition, most poisoning results from the consumption of tea made from seeds for its hallucinogenic effects.

Also, be mindful when touching the plant, especially when pruning, as the sap can irritate your skin.

4 – Buxus sempervirens (Common Box)

buxus sempervirens common box plant


The Common Box is often found in gardens, with their evergreen and compact leaves making them perfect for shaping ornamental displays.

Also, they provide a great habitat for local wildlife, like small birds and beneficial insects.

Potential harm

Ingestion of buxus may cause stomach nausea, vomiting, diarrhoea, and in extreme cases respiratory failure.

The leaves are poisonous to humans but the unpleasant odour and bitter taste tends to minimise its ingestion. Even touching the leaves can cause minor skin irritation, so wear gloves when handling.

5 – Galanthus nivalis (Snowdrop)



Well-recognised as a symbol of winter’s end, the Snowdrop is a popular flower, earning the RHS Award of Garden Merit.

And it is popular with bees thanks to the pollen-rich flowers it produces.

Interestingly, these flowers were not named after ‘drops of snow‘. But instead, they were named after a particular style of earring!

Potential harm

Poisoning most occurs when the bulbs are mistaken for onions and ingested, as they contain alkaloid compounds.

Snowdrops can cause nausea, diarrhoea and vomiting if eaten in large quantities. Therefore, be mindful of pets that like to dig in the garden.

6 – Helleborus (Hellebore)

Helleborus hellebore


Hellebore is a lovely, easy-to-grow flower, and there are several varieties with different shades of bloom to enjoy.

These include green, white, red, or pink! And these flowers aren’t just ornamental, as bees absolutely love them.

Potential harm

Ingestion of the plant may cause severe discomfort. The roots are emetic (a substance that causes vomiting) and are potentially fatal.

There is also the chance of slight skin irritation after touching the plant, so wear gloves when handling.

7 – Prunus laurocerasus (Cherry Laurel)



This spreading evergreen shrub produces lovely white flowers in erect racemes, followed by cherry-like red-to-black berries in the autumn.

Moreover, they grow up to 1m, which makes them ideal for screening and creating architectural shapes in your space.

Potential harm

The leaves and fruit pips contain cyanolipids. Notably, these are capable of turning into prussic acid, hydrogen cyanide, a very dangerous poison.

You should be particularly aware of this if you have dogs and cats.

8 – Narcissus (Daffodil)

Narcissus daffodil


Daffodils are a familiar sight in UK outdoor spaces, particularly heralding that spring is truly underway. This beloved flower is the birth flower for March and the national flower of Wales. It has been enjoyed in the UK for many years.

Potential harm

All parts of the daffodil contain a toxic chemical, lycorine, but the highest concentration is in the bulb. However, eating any part of the plant can cause symptoms such as nausea, abdominal pain, and diarrhoea.

Be mindful of children or pets who may dig up the bulbs.

9 – Rheum rhabarbarum (Rhubarb leaves)

Rheum rhabarbarum Rhubarb


Not only a delicious vegetable, thanks to its bright red stalks, Rhubarb makes for an attractive sight. Very tasty in pies, drinks, and other sweet treats, this vegetable is quite tart raw.

Potential harm

Whilst the stalks are completely harmless, rhubarb leaves are toxic and contain high levels of oxalic acid harmful to humans and can lead to your throat closing up. Furthermore, during World War 1 the leaves were mistakenly recommended as a food source in Britain, resulting in many people being poisoned.

As a matter of fact, oxalic acid is used in ink, stain remover and metal polish, so safe to say is definitely not edible.

10 – Convallaria majalis (Lily of the valley)



This beautiful low-growing perennial plant with its bell-shaped flowers are a magical sight in gardens. They also have a lovely scent, adding to its charm.

Potential harm

Lily of the valley is extremely toxic when ingested, as it contains glycosides. These play several key functions in living beings. As you might surmise the ‘gly’ element of the word refers to glucose. The glycoside is activated by the addition of water which breaks down the sugar entity. So, if you chew the leaves, the salvia breaks down the sugar, and chemicals that are not good for us are released.

Convallotoxin is one of the most active natural substances affecting the heart; it causes irregular, slow pulse rates and can cause heart failure.

11 – Laburnum (Common Laburnum)

laburnum common laburnum


These enchanting flowers are a pleasant sight when they flower between May and June.

Specifically, the golden hanging blooms drip from the branches and are often trained over pergolas, arches, or walkways.

Potential harm

All parts of Laburnum trees are extremely toxic when ingested, so keep in mind before planting if you have curious pets.

To clarify, they cause nausea and vomiting, and only 15 seeds or more can be lethal when ingested by a human adult.

12 – Aconitum napellus (Monkshood)

Aconitum napellus monkshood wolfsbane aconite


The tall spires of this perennial are what make it a welcome and attractive addition to gardens.

Their lovely purple-blue flowers appear in mid to late summer. And their flowers are much enjoyed by pollinators, particularly bumblebees.

Potential harm

This plant is steeped in historical lore and mythology thanks to its poisonous toxin, aconitine. Otherwise known as wolfsbane, it has been recognised for centuries for its lethal elements for centuries.

Also, it was used in ancient times as the poison of choice on spears and arrows for hunting and warfare. Similarly, it got this name as it was used to poison wolves in Europe.

Whilst these plants all have harmful properties, they are still wonderful additions to the garden. Also, by being aware of their dangers helps you to make an informed decision, especially if you have young children and pets.

Find out how to ensure your garden is ideal for your furry friends:

Or check out my Pinterest board for more ideas: