Types of Thistle UK

The Creeping Thistle

Of the different varieties of thistle in the UK, the Creeping thistle is by far the most common. It is a perennial plant that spreads very easily via seed and also by using its’ powerful rhizomes and roots. The Creeping thistle is considered a weed, and its rapid reproduction has earned it the title of an invasive plant.

Although it is a weed and probably not the most attractive member of the garden, the Creeping thistle does a fantastic job of supporting the local ecosystem. It is a haven for wildlife, attracting birds, bees, butterflies and other small invertebrates as they search for food.

Several reliable methods are available to control this variety of thistle. Restricting the seed distribution is extremely effective. Simply remove the flower buds before they turn purple, this will prevent the seeds from ripening and being dispersed on the wind. Other methods include digging the plant out or treating with a herbicide.

Identifying UK Thistle Varieties

It’s quite easy to identify a thistle – the bracts found underneath the flower are always spiky. There are different sizes of thistle species; some will have stiff spikes, others soft prickles. Another common feature is their purple flower, although a small number have a yellow flower, such as the Cabbage and Carline thistles.

• Creeping thistle is a perennial, invasive, short to medium-height plant with wavy, spiky leaves and pink-purple flowers. It has far-reaching underground rhizomes and is found throughout the UK.
• Spear thistle is a medium-tall annual plant growing to around 1.5m. It has a spiny stem and deep pink flowers. It is widespread and common throughout the UK. The Spear thistle is native to Scotland and is their national emblem.
• Welted thistle is tall, growing to 2m and found in damp areas. It has soft-spined leaves, a sharp branched stem and reddish-purple flowers.
• Marsh thistle is medium to tall, found in damp grasslands and common throughout the UK. It has purple clustered flowers and a very hairy, spiny stem and leaves.
• Sow thistle is unusual having a yellow flower. It has hairless, blueish leaves and is a medium perennial, growing to 1.5m. It propagates via seed and rhizome.
• Milk thistle is a robust perennial with large rosettes of spiny leaves topped with purple flower heads. It is native to the Mediterranean.

Are Thistles Invasive?

Sadly, the Creeping thistle is another plant considered to be invasive due to its incredible ability to grow anywhere and spread quickly. It is usually kept in check by neighbouring perennial grasses, but when it gains control, it can be very invasive.

Similar to Japanese knotweed, the Creeping thistle has underground rhizomes that allow it to spread. It rarely propagates by seed as they are usually infertile, but the powerful rhizomes can lie dormant in the soil for years and will begin to grow and expand if there is a growth opportunity.

Creeping thistle plants are native to the UK and can be found in most areas. Often they inhabit verges, grasslands, woodland and hedgerows. They will grow in almost any soil and if left unchecked, they can form a dense thicket of up to 20m in just two years.

Thistle Benefits

Whilst prickly and not particularly attractive, some types of thistle offer valuable health benefits. Probably the most well-known is Milk thistle, which is used in herbal remedies to protect the liver from toxins. It also helps the liver to repair itself. Milk thistle is thought to help manage diabetes, improve indigestion and lower cholesterol as well. It’s a very medicinal plant!

A little-known fact about thistles is that every single variety is edible. They also taste good—plants with spines do not need to deter predators with taste, so they often have a pleasant flavour. The young leaves of a Sow thistle are high in vitamin C and can be used in salads. The thistle plant in general is extremely nutritional. When compared to other vegetables, thistles have a higher level of fibre, protein, phosphorous, magnesium, calcium, copper, zinc and other nutrients!

Creeping thistle plants spread easily through their strong rhizomes and effective seed propagation meaning dense thickets of this spiky, unforgiving plant can appear quickly. If you need advice on how to treat, remove and control an invasion, get in touch with the team here at The Knotweed Specialists. Tackling plant invasions is our speciality.