29 Bull Thistle Facts: All About This Invasive Plant Species

Bull thistle (Cirsium vulgare) is a spiky biennial weed that can be found in meadows, along roadsides, and in croplands all over the United States.

These invasive plants have purple flowers. Bull thistle can be found in the woodlands and hayfields. These plants are native species of Europe, North Africa, western Asia.

In rosette form, the plant can grow 2-7 ft (60.96-213.36 cm) tall with prickly leaves. The bull thistle is a plant native to Europe, Asia, and Africa.

When the seeds were mistakenly transported into the country with crop seeds in the early 1800s, the weed was accidentally introduced to the United States. Cultivation, regular cutting, and tilling will help reduce the growth of Bull Thistle (Cirsium vulgare) of an area, new infestations, and seed production.

The leaf lobes of Bull Thistle are spear-shaped and have spiny wings. If you have these weeds in your garden, remember to collect the flowering stems and destroy them to stop the formation of viable seeds.

During the latter year of the plant's life, bull thistle flowers in July and August. Each flower head is around 2 in (5.08 cm) in diameter. Hundreds of seeds form swiftly from the flower heads.

The wind is in charge of distributing the seeds. Each seed has a 10-year life span.

Bull thistles tend to grow in open areas with plenty of sunlight. The plants are tolerant of both wet and dry soil conditions.

The overgrazed pasture area is especially sensitive to bull thistle invasion. While unofficial, the bull-thistle (Cirsium vulgare) is considered the Chenango County Flower, and according to folklore, 'Chenango' is an old Indian word meaning 'bull-thistle' or 'country of the bull-thistle'.

Bull thistle Classification

• The scientific name of these invasive plants is 'Cirsium vulgare'. It is also called a 'common thistle'.
• This plant is a ruderal species that colonize the bare ground as well as thrives well on heavily grazed land.
• The proliferation of this plant gets increased by the nitrogen present in the soil surface.
• The flowers of the bull thistle are a very good source of nectar which are used by many pollinating insects, like honey bees, butterflies, and wool-carder bees. Linnets, greenfinches, and goldfinches eat the fruit of this plant.
• The seeds get dispersed by mud, wind, water, and insects as well. The young thistles grow immediately just after getting dispersed.

Lifecycle Of Bull Thistle

The lifecycle of a bull thistle:

• In the first year, bull thistle will grow a rosette of leaves close to the ground.
• In the second year, the plant will send up a stalk with flowers.
• After the flowers are done blooming, the seeds will be dispersed and new plants will grow from them.
• Bull thistles reproduce by both seed and stem fragments.
• The dark green leaves and flower heads of bull thistle have sharp spines and have a waxy coating that makes them resistant to drought.
• The flowers are purple or pink and are pollinated by bees.
• The seeds are small and light-colored with one black spot on each one. They germinate in late summer or early fall when conditions are warm and moist.
• Bull thistle can be a nuisance because it grows so quickly and can crowd out other plants. It is also difficult to remove once it becomes established. However, the flowers are pollinated by bees and the seeds provide food for birds, so there may be some benefit to allowing a few plants to grow.
• Bull thistle is native to Europe and Asia but has been introduced in North America where it now occurs in all states except Hawaii.

Is bull thistle an invasive species?

Bull thistle, or spear thistle, is a weed that can be found throughout the United States.

• It is considered an invasive species in some locations, and it can cause problems for farmers and other landowners.
• Cirsium vulgare can be difficult to control, and it often spreads quickly.
• If you see a bull thistle on your property, it is important to take steps to remove it as soon as possible.
• Otherwise, it may continue to spread and cause damage. These weeds, if grown on a grazing ground, will even harm the food of grazing animals.
• Their effectiveness is largely due to the fact that they use a variety of dispersal mechanisms, including air and animal movement.
• Because of their lightweight and sail-like heads, the seeds can move for miles in the wind. They are also a source of food for small birds, and herbivorous mammals can eat them while grazing on the bull thistle leaves.
• Allelopathy was discovered in Canada thistle, which means it secretes substances out of its roots that are poisonous to other plants, providing it an advantage.
• Thistles are known for sucking up nutrients from the soil all over them, making them a serious threat to pastures and crops.
• They also use a lot of water, which can dry out the soil and make it more prone to erosion.

How To Control Bull Thistle Growth

These thistles can be pesky weeds to control.

• Treatment should begin early in the spring before the plants have a chance to blossom and set seed.
• There are several techniques that can be used to control bull thistle growth, which include chemical control, mechanical control, and many more. Some of them are discussed here.
• Mechanical removal is one of the most effective ways to remove bull thistle.
• This can be done by using a weed wrench or by hand pulling. Be sure to remove all of the plant, including the roots, or it will regrow.
• Herbicide application is another option for controlling bull thistle growth.
• There are lots of herbicides that can be used, but make sure to read the label carefully and follow all of the instructions.
• Cultural practices can also be used to control bull thistle growth. This includes mowing and grazing. Mowing will remove the top part of the plant, but it will regrow if not done regularly.
• Grazing is a more effective method, but it can only be used if there is enough livestock to do so.