The summer brings a wealth of outdoor activities for children, including exploring the nooks and crannies of their own gardens.

But there could potentially be toxic plants around every corner, from monkshood and laburnum, to hemlock, aquilegia, autumn crocus (colchicum autumnale), lords-and-ladies and hellebores.

These are all common plants you might find in your garden or in a hedgerow, and all have different levels of toxicity. The amount you would have to ingest to do real damage varies from plant to plant.

Gardeners tend to be more at risk from touching a plant which may cause a skin irritation from its sap, or an allergic reaction.

A small number of plants may also cause the skin to be excessively sensitive to strong sunlight, resulting in severe localised sunburn and blistering.

Giant hogweed (Heracleum mantegazzianum) and garden rue (Ruta graveolens) cause a phototoxic reaction. Irritation, pain and blisters result from exposure to plant sap in bright sunlight. Curious children may also put flowers or leaves into their mouths which are poisonous.

Many plants give off their own warning signs. Some have an unpleasant taste which reduces the likelihood of a dangerous quantity being eaten, while others just do not look edible.

Here are five of the most common toxic plants:

1. Monkshood (Aconitum)

Often planted under trees or spring-flowering shrubs at the back of a border, bearing tall spikes of helmeted flowers in blues and purples in the summer, all parts of the plant are poisonous and a skin irritant, causing burning of the lips and mouth, intense vomiting, diarrhoea and spasms.

Historically, monkshood was used by people to commit suicide by eating the leaves. Hunters in the Amazon rainforest also poisoned the tips of their arrows with it to kill animals.

2. Laurel

Many of us have laurel in our gardens - it belongs to the family that includes apple, cherry, plum and almond. But be warned that when you chop your laurel hedge the sap gives off an unbelievably soporific effect and you may fall asleep.

3. Foxglove (Digitalis)

Both the wild and hybrid varieties produce tall spikes bearing bell-like flowers in a variety of colours, and are often grown in partial shade, reaching heights of up to 2m (6ft). All parts of the plant are poisonous.

4. Glory Lily (Gloriosa superba)

These beautiful summer-flowering climbers, producing red flowers with yellow tips, are often grown on a south-facing patio or in a sunny, sheltered spot. But their beauty belies their toxicity and every part of the plant - particularly the corm - is poisonous.

5. Rue (Ruta graveolens)

A native of the Balkans, this plant with pretty yellow flowers was historically grown as a medicinal plant known for its anti-bacterial, anti-viral and anti-inflammatory properties.

However, its herbal uses may become insignificant if you get sap on your skin, which in sunlight can cause a blistering reaction which can last for weeks.

What to do in an emergency

If you think your child has eaten part of a poisonous plant or suffered an allergic reaction to it, don't panic but do seek medical attention from the accident and emergency department of your local hospital, taking a plant sample with you, the RHS advises.

The main message from the charity is that you should be aware of the plants which are toxic - and teach your children that if it isn't a recognised food, don't eat it.

A full list of poisonous plants is available at the RHS website (rhs.org.uk).