Creeping thistle is a

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

A large, tapering, central root that grows downward. It's typically thicker and deeper than the other roots, allowing access to water and nutrients from deeper in the soil. Plants with taproots include dandelions, carrots and parsley.

taproot

A branch that grows from the main trunk or trunks.

lateral

A bud is a small, undeveloped shoot that contains the potential for new growth. Buds are typically found on stems, where they can be apical (found at the tip) or axillary (found between leaf axils) and may develop into leaves, shoots or flowers.

buds

A native plant is one that originated or arrived naturally in a particular place without human involvement. In the British Isles, native plants are those that were here during the last ice age or have arrived unaided since.

native

Creeping thistle is a UK native wildflower, commonly found throughout the country on grassland, waste ground, roadside verges and field margins. It is a valuable plant for wildlife, providing food for a range of invertebrates, including caterpillars of the painted lady butterfly. Its flowers provide nectar for moths and butterflies, including the small tortoiseshell, white letter hairstreak, peacock and meadow brown, and nectar and pollen for bees. Its seeds are also an important food source for a variety of farmland and garden birds, including goldfinches, greenfinches, siskins and lesser redpolls, many of which also use the thistledown for nest building.

Here are our answers to your most common questions about dealing with creeping thistle: 

How invasive is creeping thistle?

As its common name suggests, creeping thistle spreads to form large colonies. Its roots and rhizomes are brittle and regenerate easily if broken up by digging.  

As most plants are dioecious, and large clumps tend to be clones of a single plant, the flowers of creeping thistle are rarely pollinated, and thistledown is often devoid of seed or contains unviable seed. However, when they are pollinated, plants produce an abundance of seed, estimated to be around two hundred per flowerhead, several hundred per stem and thousands per plant. Being wind-pollinated, they can travel some distance from the parent plant and are able to grow, flower and set seed themselves within a year.

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Each seed is attached to a bundle of fine hairs, allowing it to travel far on a slight breeze   

Do I need to get rid of creeping thistle? 

In the unlikely event that you are served with an order under the Weeds Act 1959 to control creeping thistle on your land, then you must comply with this. However, in most gardens it is not necessary to completely eradicate it. Allowing some to grow in a meadow, wildlife corner or less-cultivated area is a great way to boost the biodiversity of your garden and gives you the chance to enjoy its attractive flowers.

It is, however, a good idea to control creeping thistle to stop it spreading to parts of your garden where it might smother and outcompete other plants.   

What is the easiest way to kill creeping thistle? 

If you have creeping thistle growing where it is not wanted, there are several ways to control it: 

• Deadhead – remove faded flowers in summer before they run to seed. 
• Hoe off seedlings – do this promptly, within the first few weeks of them appearing, before roots produce adventitious buds which they can regenerate from. Hoe on a warm, dry or windy day, so exposed roots dry out quickly. 
• Dig or fork out plants – ideally do this when plants are still young and haven’t had time to develop an extensive root system or set seed. As well as removing the main clump of growth, it is important to carefully sift through the adjacent soil to remove as many roots as possible. Remove regrowth promptly, before it becomes established.  
• Pull off top growth regularly – this is a good option for controlling awkwardly positioned plants and has the benefit of not disturbing the soil. Wearing thick gloves, simply pull off all above-ground growth as it appears through spring and summer. This weakens the plant, by preventing photosynthesis, and will eventually kill it. Pulling is better than cutting off top growth, as regrowth has to come from root buds, which expends more energy. 
• Smother seedlings – thistle seedlings are sensitive to competition for light so apply a mulch of organic matter, around 10cm (4in) thick, to your soil in early spring to smother emerging seedlings. Alternatively, fill gaps in borders with ground cover plants.  
• Smother established plants – cover soil with a layer of compostable material, such as cardboard, and then a layer about 20cm (8in) thick of organic matter, such as bark or wood chips. Alternatively, use a heavy grade biodegradable mulch matting. This will block light and prevent growth, causing the root system to die. Keep soil covered for a few years, topping up the mulch layer if necessary, to ensure this method is effective. 
• Avoid disturbing the soil – creeping thistle easily regenerates from root fragments, so avoid routine digging or hoeing in parts of the garden where it grows.

Should I use a weedkiller? 

No – as non-chemical control methods are effective, even if time-consuming, there is no need to use a weedkiller.  

The RHS does not support the use of weedkillers and recommends that alternative control methods are used. However, we do note that when gardeners struggle to control plants with cultural methods, regulated weedkillers/pesticides for home gardeners are available for use legally. Garden centres and large retailers selling weedkillers have trained staff who can advise on suitable products for your needs.