Cirsium vulgare

It’s a real bugbear of mine that, in the current dry and hot weather cycle, all the cultivated flowers and shrubs in the garden are struggling and yet most of the weeds are growing vigorously. This month, I’m noticing very strong-looking spear thistles springing up and flowering (also known as bull, or common, thistles). Did you know that spear thistle is one of five plants listed under the Weeds Act 1959 as an ‘injurious weed’? Others listed in the Act are common ragwort, curled and broad-leaved dock, and creeping thistle. Spear thistle is, of course, a valuable source of nectar for bees and butterflies. Smaller birds, such as goldfinches and linnets, also feed on spear thistle seeds. However, whilst it plays a part in our natural ecosystem, its prickly presence is not a welcome sight for farmers, gardeners and landowners. Spear thistle removal can prove difficult - an infestation will be persistent, partly due to the very deep tap root that can anchor itself into the ground. It can also spread very quickly. Spear thistle seeds have silky pappus hairs which are designed to be carried effectively by the wind. A single spear thistle seed head can produce about 100 seeds which once airborne mostly fall within the first 40m, however they can still potentially reach a neighbouring field or property. It can cause real damage to agricultural land by dominating other plant species and reducing the quality of crops as well as grazing land. Livestock will generally try to avoid spear thistle because it is so sharp and prickly, but if ingested by an animal it can cause painful injury and result in a call to the vet.

Although my own garden is a bit of a jungle, I don’t yet have any of this thistle (plenty of brambles though). My photo was taken on the footpath to Tesco in the village.