Prickly lawn weeds are the worst. They don’t just ruin the aesthetic of your lawn - they’re darn painful to step on! I talk about the most common culprits here. Thorn apple is a weed that prefers a warmer climate than Britain, but in hot summers they are quite commonly found. Another common name, devil's snare, sounds alarming, but a few simple precautions will enable gardeners to handle this weed without great risk. Datura, a night-blooming flower sometimes raised in home gardens, is also known as Jimsonweed or Thornapple (Datura stramonium). Jimsonweed is a contraction of Jamestown and is the name that early settlers and British soldiers gave the plants. Thornapple is an appropriate common name because it aptly describes the …
Prickly Lawn Weeds (7 Different Types)
It’s a brand new morning with the birds singing and a soft, gentle breeze. A hot cup of coffee sits in your hand, the steam and aroma waft up as you take a deep breath. You place your bare feet onto your soft, spongy turf then… ouch! You found a prickly lawn weed! When this happened to me, it meant war, and I set out to identify, research, and destroy every last spiky weed on my lawn.
Stick around while I identify different types of weeds with thorns and tell you how to get rid of each type of prickly weed you may find on your lawn.
Most Common Prickly Lawn Weeds (Short Answer)
Burr Medic, Goat Head Weed, and Lawn Burweed are low-growing prickly lawn weeds. Spiny Sowthistle and Spiny Cocklebur are high-growing spiky weeds you may see on your lawn that can release painful burrs you may never see. Carolina Horsenettle and Jimson Weed are nightshade relatives and are both weeds with thorns on their stems.
A Closer Look at the Different Prickly Lawn Weeds
Some weeds may give you a prick when you touch them, while others may stick into your flesh as you pass. One thing is for sure, none of them are good for your lawn. Anything that scratches, pokes, stabs, or slices needs to be removed from your turf ASAP.
Below I’m going to talk you through some of the most common types so you can identify and then hopefully remove them too, restoring order to your lawn.
Burr Medic (Medicago polymorpha)
What It Does: This lawn weed with thorns grows low and, sporting trifoliate leaves, blends in with clover in a yard. Burr medic puts up small yellow flowers in March and June and then produces seed pods. By late summer, the pods dry up and open, dumping several seeds across the turf. These pods have spikes that allow them to hitchhike and spread throughout your lawn.
What It Looks Like: Burr Medic is related to Black Medic and resembles Clover. It has a thin, smooth, red-purple stem and produces oblong, green leaves. The leaves alternate along the stem in groups of three. The leaf tips are serrated and appear sharper than other trifoliate weeds. These prickly lawn weeds produce yellow pea-shaped flowers that are arranged in clusters of 2 to 10. Seed pods are green to brown with a sharp hook.
How to Get Rid of It: You can remove a small patch of these spiky weeds by hand, but make sure you wear gloves. It is best to remove them when you see the yellow flowers before they drop seeds. If there is a larger area of Burr Medic, you can use a broadleaf herbicide to kill it.
Goat Head Weed (Tribulus Terrestris)
What It Does: A fast, low-to-the-ground prickly weed that can grow a dense, prostrate stem mat up to 5ft long. Goat Head Weed overtakes dry, damaged, and neglected areas and then creates tons of inconspicuous flowers. As these flowers die away, seed pods are formed with several pointy spikes. These barbs can grab onto anything and get spread far and wide. They grow a deep taproot that can be hard to separate from the turf.
What It Looks Like: Goat Head Weed goes through several lifecycle stages and can be hard to identify before it’s too late. In the early stages, on a lawn, it will be hard to see and identify. As it grows large, the stem will remain erect in a crowed area to compete for light. In the open, it will sprawl across the ground and not stand upright. When it blooms, you will see bright yellow flowers with 5 petals each, roughly the same size as the leaves of the weed. These spiky weeds on your lawn turn reddish-brown after they flower.
How to Get Rid of It: While there are many ways to kill this weed, its complete destruction and the removal of all seed burrs are very difficult. To kill the plant, you can burn it with fire until the mass above the taproot is charred. Vinegar with 5% acidity or higher and herbicides like glyphosate and oryzalin are also effective. Once the weed is dead, you can rake or pull an old carpet over the area to collect the dreaded Goat’s Heads.
Lawn Burweed (Soliva sessilis)
What It Does: Found in thin and patchy turf, these prickly weeds on your lawn can be a real nuisance. Lawn Burweed germinates in the fall and grows through the winter when turf may be dormant. When the temperature warms up in the spring, these weeds produce buried seed pods that are carried throughout the lawn all summer and cause a painful sting when stepped on.
What It Looks Like: Early detection is key to preventing these burrs from occupying your lawn. Burwood grows low and branches freely. It has small, grayish-green leaves that grow opposite and are sparsely hairy. It produces small, ¼ of an inch flowers that can go almost completely unnoticed on a lawn. These flowers are replaced by small spine-tipped burrs that are often felt rather than seen.
How to Get Rid of It: Maintaining a thick, lush lawn throughout the winter months will prevent prickly lawn weeds like Burweed. If you can identify it in winter, you can use post-emergence herbicide through December, January, and February. After that, it will be hard to control without killing your turf and you should pull up (with gloves) and rake what you can and plan to attack next winter.
Spiny Sowthistle (Sonchus asper)
What It Does: Not a true thistle, this spiky weed starts with a basal rosette that closely resembles thistles. Spiny Sowthistle grows in neglected areas and can get up to 6ft tall. The leaves of this plant are very prickly and the flowers develop from spiky buds. It exudes a milky sap when cut that is quite sticky. Accidentally hitting these prickly weeds on your lawn with a weed whacker can create a sticky, spiky mess.
What It Looks Like: Spiny Sowthistle resembles a spiky dandelion. It has similar leaves, albeit much more prickly, that are a similar bluish-green. It produces the same yellow flower and the same tuft of white seeds. It is much larger than a dandelion and spreads rapidly.
How to Get Rid of It: Manual removal of Spiny Sowthistle is possible if the area is small. Wearing gloves, full skin coverings, closed-toed shoes, and eye protection, you can dig out the roots of this weed in the spring before it flowers. To discourage regrowth, you can pour vinegar around the base of the weeds. For larger areas, you will need to apply 2,4D or glyphosate herbicide to each plant before it flowers. After the plant dies back, dig it up by the roots and reapply the herbicide into the hole where you removed the weed. Do this until they stop coming back.
Spiny Cocklebur (Xanthium spinosum)
What It Does: High-growing lawn weeds with thorns, these invaders can reach 3 and a half feet tall. They produce a deep taproot and take over dry, disturbed territory. When the flowers die, a two-chamber burr is released. Each burr has two seeds, one germinates that following spring but the other delays for 2 or more years. Complete removal is a multi-year process.
What It Looks Like: An erect stem with many branches, this tall annual has yellow, 3-parted spines. The leaves are lance-shaped, 2 inches long, and smooth on top. Each leaf is shiny, dark green, and has small white hairs on its underside. The flowers are inconspicuous cream to green in color and bloom from December to May.
How to Get Rid of It: Hand removal and chemical treatment are both effective ways to eliminate these prickly lawn weeds. For hand removal, you will want to wear full protective gear, as these weeds can irritate the skin. Pull up all Spiny Cocklebur and any seedlings and dispose of them – don’t compost the waste! You will need to repeat this each spring for the next few years. Mowing on your highest lawn setting once a week during the early spring and as frequently as needed during the late spring can prevent Cocklebur from producing seeds. A post-emergent herbicide applied at the start of the year can also be effective.
Carolina Horsenettle (Solanum carolinense)
What It Does: A member of the nightshade family, it is not a nettle but grows like one. It occupies dry and damaged turf. While the fruit of these weeds may look like tiny tomatoes, they are toxic to people and pets, and simply touching the plant can cause you to break out in rashes. They grow tall and emerge in spring when they choke out thin turf. Worst of all, they are lawn weeds with thorns on their stems and leaves.
What It Looks Like: Carolina Horsenettle looks like a spiky vine that creeps across the ground. They have prickly, oblong, dull green leaves that are about 2 to 6 inches long. These prickly weeds bloom from May to September and open between 5 and 20 pale violet, star-shaped flowers. The fruits look like little tomatoes, but turn from green to yellow and never turn red.
How to Get Rid of It: Getting rid of these types of weeds with thorns can be very tricky. It spreads by creeping roots and root fragments, as well as by seeds. Each plant can produce 5,000 seeds. Hand-pulling is not advised because of the long thorns that can penetrate even gloved hands. A glyphosate herbicide can be sprayed or painted onto the weeds. After the weeds die off in a few weeks, they must be dug up and another application of herbicide should be applied to the holes to kill any root fragments. Repeat as needed.
Jimson Weed (Datura stramonium)
What It Does: Another spiky relative of the tomato, Jimson Weed produces big poisonous fruits encased in a spiky shell. Jimson Weed can grow to several feet and produces flowers from May to September. They create spiky seed pods that burst open and spill hundreds of seeds all over the place.
What It Looks Like: A broadleaf annual, this prickly lawn weed can grow to 4ft tall. The leaves are lanced-shaped, oblong, and about 2in long. The colors of the stalks and stems of these weeds can range from green to purple. Each flowering stem produces a single white, trumpet-shaped flower that opens to around 2 inches.
How to Get Rid of It: While wearing gloves, you can hand pull Jimson Weed before it produces seeds. Place all yard waste in a bag and dispose away from your lawn. Repeated pulling of infested areas should yield a weed-free yard in a few seasons. A selective herbicide can be used to treat a larger area where this invasive plant is present.
About Tom Greene
I’ve always had a keen interest in lawn care as long as I can remember. Friends used to call me the “lawn mower guru” (hence the site name), but I’m anything but. I just enjoy cutting my lawn and spending time outdoors. I also love the well-deserved doughnuts and coffee afterward!
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Datura stramonium (thorn apple)
Thorn apple is a weed that prefers a warmer climate than Britain, but in hot summers they are quite commonly found. Another common name, devil’s snare, sounds alarming, but a few simple precautions will enable gardeners to handle this weed without great risk.
Latin name Datura stramonium
Common name Thorn apple
Life cycle Annual
Areas affected Uncultivated ground, beds, borders
What is Datura stramomium
Datura stramonium (or thorn apple as it is commonly known) is an annual weed of gardens, roadsides and other waste or cultivated land. It is widely naturalised in warmer countries throughout the world, and is quite common in the British Isles, often appearing in waste and cultivated ground.
Although quite a striking plant, it is as well to be aware that all parts, particularly the seeds, are highly poisonous. It belongs to Solanaceae, a family which includes the potato and tobacco, and many members of this family contain toxic substances. This page looks at options for gardeners when Datura stramonium is becoming a problem.
This weed can grow to heights of 1m (3¼ft). It flowers from July to October with wide, funnel-shaped flowers. These are usually white but plants with purple or lilac flowers and purplish stems are referred to as Datura stramonium var. chalybaea (syn. D. stramonium var. tatula).
It produces seedpods which are large and spiny (hence the common name thorn apple) though plants with spineless seedpods are known and these are referred to as D. stramonium var. inermis.
The leaves very broad and coarsely toothed.
The potentially harmful poisonous and hallucinogenic properties of this plant can sound alarming especially when made much of in the media. The leaves and seed pods also look exotic and alien. In fact this is quite a small plant and not very invasive in Britain. Common sense precautions limit risk factors so that gardeners need not be too alarmed by this weed.
The seed appears to retain its viability for many years when buried and germinates when the soil is disturbed. Spread is facilitated by human activities – in gardens it appears to be a contaminant of birdseed.
The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.
There are a number of non-chemical control options.
Dig, pull or hoe out plants before seed is set. Seedlings and plants that have not set seed can be added to the compost heap where the toxins will naturally break down. However, plants that have set seed should be consigned to the green waste collection, buried deeply (60cm/2ft or more) or burnt in order that the seed does not disperse in the garden or persist in the compost heap. Always wear gloves or thoroughly wash hands after handling this plant.
Use a mulch of organic matter, at least 5cm (2in) thick or opaque sheeting, such as woven polypropylene, to smother this weed.
Contact herbicides such as acetic acid (eg. Weedol Gun! Fast Acting, Roundup Speed Ultra, Spot On Fast Acting Weedkiller or Resolva Fast Weedkiller), fatty acids (eg. Job Done Garden Ultrafast Weedkiller) and pelargonic acid (eg. Doff 24/7 Fast Acting Weedkiller, Roundup NL Weed Control or Resolva Xpress Weedkiller) are good at knocking back young annual weeds such as thorn apple. Systemic herbicides such as glyphosate (e.g. Roundup Fast Action, SBM Job done General Purpose Weedkiller or Doff Advanced Concentrated Weedkiller) will also be effective and can be used when mature plants need to be eliminated.
These herbicides are non-selective and so care should be taken while spraying near other plants. Plants to be avoided can be covered with a bucket/flowerpot or screened with plastic when spraying.
Inclusion of a weedkiller product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.
Weedkillers for gardeners (Adobe Acrobat pdf document outlining weedkillers available to gardeners; see sections 3a and 4)
What Weed Has a Round Prickly Seed Pod?
Datura, a night-blooming flower sometimes raised in home gardens, is also known as Jimsonweed or Thornapple (Datura stramonium). Jimsonweed is a contraction of Jamestown and is the name that early settlers and British soldiers gave the plants. Thornapple is an appropriate common name because it aptly describes the round, prickly seedpod that develop after the spent flowers fall off the plant. The prickly seedpods prevent animals from eating the toxic seeds.
Jimsonweed grows to heights of between 1 and 5 feet. Its leaves’ edges are toothed edges and nearly egg shaped with pointed ends. Their length ranges from 2 to 8 inches. Funnel-shaped flowers are 2-1/2 to 4 inches long and open to a trumpetlike bell in white, violet or lavender. The plant’s fruit is a spiny pod measuring roughly 2 inches in diameter. The seedpods grow as they ripen and the seeds mature. Ripe seedpods burst open, scattering the seeds.
- Jimsonweed grows to heights of between 1 and 5 feet.
- Its leaves’ edges are toothed edges and nearly egg shaped with pointed ends.
Most species are low-growing, shrublike or spreading perennials or are prolifically reseeding annuals. D. wrightii is the species that is common to the Western United States. Rank-smelling leaves and large, white flowers that are occasionally tinged with purple characterize this plant. A sprawling perennial, the plants have enormous taproots that may extend deeper than 2 feet into the ground. Its geographic range extends from California to Utah, Arizona, New Mexico and into Texas. D. wrightii is considered a cosmopolitan annual weed that seeds prolifically. D. discolor is a native species found in riverbeds and desert washes in Arizona and southeastern California. It has smaller flowers. D, stramonium is naturalized throughout the United States. D. stramonium is distinguished from D. wrightii because the plants have smaller flowers and a more erect growing habit.
- Most species are low-growing, shrublike or spreading perennials or are prolifically reseeding annuals.
- D. discolor is a native species found in riverbeds and desert washes in Arizona and southeastern California.
The contraction of “Jamestown weed” is the origin of the name Jimsonweed. Soldiers and settlers were poisoned after eating the plant’s leaves in salads. Long ago in India and Russia, robbers would grind up the seeds of Jimsonweed and mix them with water as a way to sedate, induce amnesia or daze people they intended to victimize and rob. Members of the ancient Indian religious order that worshipped Kali, the goddess of destruction, would also grind the seeds and feed them to people before robbing and/ murdering them. In China, Jimsonweed was prescribed for the sedative effects, for foot diseases and used for flatulence.
All parts of Datura or Jimsonweed are poisonous. Keep places where livestock graze free of the plant. Ridding an area of plants is difficult and time consuming because of the ease with which seeds spread. Some people may experience skin irritation from contact with these plants, so wear protective clothing or gear. Symptoms of Jimsonweed poisoning include blurred vision, confusion, dilated pupils, dry mouth, difficulty urinating, hallucinations and tachycardia. Although it rarely causes death, later signs of toxicity may include coma and seizures. Emergency medical attention is necessary in cases of suspected Jimsonweed poisoning. Poisoning is treated with activated charcoal and gastric lavage. Severe sinus tachycardia is treated with beta-blockers.