You know you have weeds with thorns in your land when you accidentally touch them while gardening. They help protect the mature plant from predators and disperse seeds.
Technically, some of them are not true thorns but are identified as spines or prickles. Interesting, isn’t it?
Let’s learn more about these weeds’ thorns in the following sections.
What Is A Thorn?
Thorn is a normal term for whatever sharp plant appendage pokes people, yet it has its definition. True thorns develop from modified stems or branches such as those on honey locust trees.
Meanwhile, spines are modified leaflets, leaves, stipules, or petioles. Thistles or cacti are great examples.
In comparison, prickles are modified epidural (outer) cells. You can see them on the stems of roses, raspberries, and blackberries.
In this article, I’d like to use thorns, spines, and prickles interchangeably since we aim to identify the common thorny weeds.
How To Recognize Weeds With Thorns?
It’s easy to distinguish a thorny weed from other weed types by looking at where the pointy part grows.
You can see weeds with thorns on stems and leaves, whereas other types have spines located on fruit or all over the plants.
Identifying the weeds when they’re still small and young helps the removing and cutting down process less struggle.
Thorns Growing On Fruits
Weeds with prickles can appear on the fruits at the seedling stage. A plant named cocklebur (also known as Xanthium Strumarium), growing in the hardiness zones from 3 to 11, is a good example.
It’s an annual weed widespread in fields, on wastelands, or along roadsides.
Its fruits (or burs) are egg-shaped, yellowish-green, and have spiky edges. Each bur has two seeds. These burs will keep staying on the plant when it grows.
Thorns Growing At Leaf Base
Some weed thorns only grow on the leaf nodes. For example, prickly sida (Sida Spinosa) or another name, Teaweed. The plant lives in the U.S.
The Department of Agriculture plants hardiness from zone 4 to zone 11, mostly found in pastures, crop fields, and garden beds.
You can easily spot its spines when they are still young by looking at the base of each leaf or the heart shape of the seed leaves.
This weed grows with hairy stems of eight-to-twenty-inch tall and small, yellow flowers.
Thorns Growing On Stems
Raspberries, blackberries, and other weedy brambles are weeds with thorns on the stem.
They grow well from zone 3 to zone 11 and prefer sunny and open locations such as roadsides, orchards, ditches, streams, etc.
This weed with thorns on the stem usually has long and arching stems. New plants propagate from the stems where connected to the ground or by seed.
Thorns Growing All Over
Thistles (or Cirsium spp.) are weeds that have thorns on stems and leaves. Some members of this family (the bull thistle, for example) have spines on leaves that grow near the flowers.
During its first year of growth, you can see there’s only a highly-lobed-leaf basal rosette, and the leaf margins and midrib are covered with large and stiff spines.
In the next year, it will grow up to the height of two to six feet and blossom pink flowers.
How Many Types Of Weeds With Thorns Are There?
There are 13 common varieties of thorny weeds in North America. Their spines grow on different parts, which actually helps me a lot in identifying them.
Besides, you can tell them apart by looking at their stems, leaves, and flowers. Yet, be more cautious whenever you walk once you detect any of them in your garden.
The first name on our list of weeds is Barberry. Originating from Europe, this shrub can reach a height of ten feet and a width of six feet.
Its flowers are yellow, its leaves are ovate, and of course, the plant has spines.
You can recognize this weed with thorns thanks to its bright yellow flowers and three-to-five-leaflet leaves.
The seeds of Beggarticks are also easily stuck on your clothes as they come with small barbs outside.
As mentioned above, blackberries are a weed with thorns on stems. It can be challenging to control your garden during summertime due to their growth.
Burrweed or lawn Burrweed is an active resident in turf choking out plants. I highly recommend you be careful with this wild plant as it has one of the most sharp and dense spikes.
The young plant starts as a rosette, and as it matures, it develops a flowering stem that grows upwards and produces yellow flowers. It blooms from late spring to early summer.
One of the common weeds is Catchweed Bedstraw. It can grow up to six feet. They tend to thrive tightly together, making matted piles of thorn weeds in the grass.
Horsenettle (solanum carolinense) is one of the common garden weeds, only between one and three feet tall (maximum 36 inches tall). It has hairy yellow alternative leaves and white or violet star-shaped flowers.
The herbaceous plant, Jimsonweed, grows rapidly in summer. Its height is at least three feet.
You can recognize it by its thick purple stem and tube-shaped white flowers, which will turn into thorny seed pods.
Some variants of nightshade are known as spiky plants, and the spines contain poison. You can find leaves’ color ranges from dark green to silver, while the trees produce purple flowers.
It’s easy to tell if you have the Prickly Lettuce in your garden. Its prickly leaves are oblong with small outer-edge spines. You also can see more noticeable spines on the underside.
Smilax is another weed that has thorns. The special thing about it is the extensive root systems making it hard to remove. The prickles around the wild vine are also an obstacle for gardeners to clean.
This prickly plant bears yellow flowers (similar to dandelion plants) and grows with sharp spines on the margin of its leaves.
Teaweed has many other names, such as spiny sida or thistle mallow. It’s all because of the related thorny feature.
The tree is mostly found in agricultural areas or open land. Fine white hairs on the green stems and small spines at the leaves base help you identify this variant.
Thistle mostly originated from the northern part of the world. It has very prominent spiny protrusions.
Its species are also diverse, yet the most detrimental is the European variety, bull thistle, whose flowers are purple and grow at the top of the tree.
The Bottom Lines
The list of Weeds with thorns usually develops in agricultural fields, pastures, and roadsides. You can identify them by examining the plant’s leaves, stems, or fruits.
They also can be considered invaders of your garden with large quantities and fast growth, requiring effective weed control.
These “ouchy” plants can cause injury, so wear thick gloves while cleaning. If the prickly weeds with thorns are small, you can pull them manually.
I advise the best time to do it for you is after the rain as the soil will be softer.