Common British Thistles | Wildlife Insight

Introduction to common British thistles

flowering heads of Spear Thistle (Cirsium vulgare) © Claire Ogden — Spear Thistle (Cirsium vulgare) © Claire Ogden

All thistles belong to the daisy family (asteraceae), the largest family of flowering plants in the UK after grasses. The flower heads are made up of a number of individual flowers or florets giving rise to this family being called “composites”.

As children we all get to recognise thistles early on since they have prickly spines that hurt, so we learn to avoid them. However, some insects use thistles to provide a safe place to build their home, protected by those sharp spines.

The leaves and nectar of thistles are very good sources of food for many insects, such as the caterpillars of the Painted Lady butterfly, and some birds, such as Goldfinch, eat the seeds making them an extremely valuable wildlife resource.

There are two groups of thistles: Carduus and Cirsium. If you’re interested in the distinction between them, it get’s a bit technical but there is a note at the end of this page.

What surprised us initially was the number of different thistles there are in the UK. This page sets out some of the key characteristics to look for to help identify the different British thistles. We’ve only included the thistles we come across most often. More details about the individual plant characteristics, the habitat they’re found in and the flowering time, as well as lots more images are given on the individual species page.

The wild flower gallery has images of other wild flowers in Britain shown by family.