Plants With Spiny Seedpods & Flowers. Curious nature lovers regularly find unusual plants poking up in their own yards or those of their friends and family. A striking vegetative combination like spiny seedpods and flowers is bound to get the attention of an onlooker. Whether you’d like to add more of your … 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.
Plants With Spiny Seedpods & Flowers
Curious nature lovers regularly find unusual plants poking up in their own yards or those of their friends and family. A striking vegetative combination like spiny seedpods and flowers is bound to get the attention of an onlooker. Whether you’d like to add more of your newfound plant to the landscape or obliterate it completely, it helps to know what kind of plant you’re dealing with. Several plants sport spiny seedpods and flowers.
Datura innoxia and Datura stramonium are both ornamental plants that grow in Sunset’s Climate Zones 8, 9 and 11 through 31. These 3- to 6-foot-tall perennials boast large, trumpet-shaped flowers and spiny seedpods. Daturas are night-bloomers that release a perfume into the moonlit garden when planted as part of a landscape. Sometimes confused with moonflower, Daturas are in no way related. Datura is a bushy plant related to imsonweed, where moonflower is a climbing vine related to the sweet potato and morning glory. Many Datura plants are poisonous, so take caution in selecting their permanent locations.
Castor Oil Plant
The most dominant feature of castor oil plant (Ricinus communis) is the mass of round, spiny seedpods that erupt after its white stalk-borne flowers begin to fade. In Sunset’s Climate Zones 23 through 28, H1 and H2, it can overwinter and grow into an impressive treelike plant. The rest of the country enjoys the unmistakable castor oil plant’s large lobed foliage during the growing season and sacrifice it to the winter, treating it as an annual in plantings. This plant’s seeds are the source of castor oil, although it is not recommended that you attempt to press your own.
Wild cucumber (Marah macrocarpus) is a beautiful native plant related to gourds, squash, cucumbers and melons. This perennial vine emerges yearly from a massive fleshy tuber and scrambles rapidly before setting delicate, white fuzzy flowers in clusters. The 4-inch-long, egg-shaped seedpod hardens into a spiny fruit containing several black seeds. Although once used as marbles and jewelry by Native Americans, the seeds are bitter and poisonous.
Prickly poppy (Argemone mexicana) thrives with abuse and reseeds itself readily when given the opportunity. The only parts of this 3-foot-tall poppy that aren’t covered in spines or sharp edges are the 1 1/4-inch-wide yellow flowers. Although treacherous, this poppy is often grown in Sunset’s Climate Zones 7 through 43, 2A, 2B, 3A, 3B, H1 and H2. The seeds germinate readily, often when one of the spiny seedpods drops to the ground and shatters.
Other plants with spiny seedpods and flowers that grow wild could be either puncturevine (Triblus terrestis) or California burclover (Medicago polymorpha). Both are considered weedy plants in many Western states. Puncturevine is mat-forming weed with small, oval-shaped leaves on long stems that generally lie along the ground. It sports small yellow flowers and produces razor sharp, spiny seedpods that can puncture bicycle tires. California burclover is a member of the pea family and strongly resembles white clover. However, its three-part leaf is made of three small leaflets, each held on its own short stem. California burclover can grow up to about 2 feet, but generally lies along the ground. Flowers are small and yellow, eventually giving way to seedpods with two or three rows of prickly hooks.
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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