Nature on our doorsteps: Thistles

Rosaleen Dwyer is the County Heritage Officer at South Dublin County Council – every week she gives us an insight into nature on our doorsteps and the beautiful biodiversity of its plants and wildlife.

ONE of the most easily recognisable plants in late summer and early autumn is the Thistle.

Thistles are perhaps best known for their green prickly leaves and for their hundreds of wispy floating seeds that are often referred to as Jinny-joes.

Two species are commonly seen, Spear Thistle and Creeping Thistle.

Spear Thistle is the national emblem for Scotland.

It is a big sturdy plant with strong stems.

It takes two years to grow, beginning in the first year as a spreading rosette at soil level of strong prickly leaves.

Spear Thistle provides plenty of pollen and nectar to pollinating insects

It likes nitrogen-rich soil, and it has a long tap root that reaches deep into the ground.

It therefore often grows in good, fertile fields and pastures.

In the second year, the stem stretches up with shorter leaves before it is topped off with robust flowerheads that look like a shaving brush.

The fat rounded base of the flowerhead is densely prickly, and supports a tuft of many long, purple flowers.

Pollinated flowers mature into fluffy seeds that spread widely in the wind.

The Creeping Thistle is our most common species of thistle, and it can be found on disturbed and cultivated ground such as rough grassland, roadside verges and field edges from June to October.

In contrast to Spear Thistle, Creeping Thistle is much more slightly built, and its prickles are not as fierce.

Because its seeds are not very fertile, Creeping Thistle spreads instead by sending out numerous side shoots to form large colonies that can sometimes cover a large area of ground.

Its flowers are also smaller, and are more pink than purple in colour, without the prickly rounded base of the Spear Thistle.

All Thistle flowers are very rich in nectar and pollen, and they are said to be one of the top ten providers of nectar to bees and butterflies.

Their seedheads are also visited by flocks of Goldfinches who pick out and eat its seeds.