If you’ve ever been cruising down the road and noticed the ditch was full of yellow flat-topped flower clusters, you may be encountering Wild Parsnip. One of the more dangerous invasive, this plant can cause severe burns and blisters if your skin contacts the sap. I’ve been eradicating Wild Parsnip for years, and can teach you all there is to know about this edible, but horrible invasive species.
In this article:
- What is Wild Parsnip
- How Wild Parsnip can hurt you
- What Wild Parsnip is bad for the environment
- Wild Parsnip Identification / Characteristics
- Wild Parsnip look a likes
- How to control Wild Parsnip
- Growing Conditions of Wild Parsnip
- What Wildlife, Pests, and Diseases effect Wild Parsnip
- Uses of Wild Parsnip
- Final thoughts
What is Wild Parsnip
Wild Parsnip is an invasive biennial wildflower/weed native to Europe and Asia. Scientifically known as Pastinaca sativa, it grows 2-6′ tall in full sun and blooms yellow flowers in Summer, spreading aggressively via seed. Once should be cautious with the plant, as it’s sap can cause severe burns and blisters on the skin when exposed to sunlight. [1] [2]
First year plants will produce a strong taproot that is edible, and has been cultivated for centuries in Europe. It is boiled, roasted, and used in soups. This however is hardly a reason to cultivate the plant, as it spreads wildly across vast fields, pastures, roadsides, and disturbed areas.[1]
And although this plant is horribly invasive, overtaking seemingly any disturbed area, it is clear that pollinators love it. In fact, nearly 100 years ago Charles Robertson documented almost 300 different species that visited Wild Parsnip for nectar or other reasons. [8] Still though, it only hosts one caterpillar species….
Look, I’ve removed my fair share of Wild Parsnip. I first learned how to eradicate Wild Parsnip from my Father who owns a 140 acre farm in the Midwest. He has been on a mission to keep Wild Parsnip off his land for more than a decade, and I must say he has been quite successful. The ditches surrounding his parcels are full of the golden yellow flowers in early to mid-Summer, while his ditches have a diverse array of species. And while every fencerow that he doesn’t control is overrun with Parsnip….. through grit, determination, and some assists from chemicals he has successfully kept the invasion at bay! [jump to how to control wild parsnip]
Wild Parsnip Range
Wild Parsnip is native to Asia and Europe. It is invasive all other places, and has colonized most of Canada and the United States. In fact for the North American continent, it is present everywhere except Mississippi, Alabama, Georgia, and Florida.
Wild Parsnip Reference Table
| Scientific Name | Pastinaca sativa |
| Common Name(s) | Wild Parsnip, Parsnip, Poison Parsnip |
| Native Range, USDA Zone | Eurasia, USDA hardiness zones 2-9 |
| Bloom Time | June-July |
| Bloom Duration, Color | 1-2 months, yellow flowers |
| Height | 2-6′ (60-180 cm) |
| Light Requirements | Full sun / partial shade |
| Soil Types | Loam to clay, rich with organic matter |
| Moisture | Moist to medium-moist soils |
| Fauna Associations / Larval Hosts | Numerous bees and butterflies / Hosts Black Swallowtail caterpillars |
Wild Parsnip poisoning / dermatitis effects
One must be careful when touching or removing Wild Parsnip not to come into contact with the sap. Or, if you do contact the sap, keep the area covered from sunlight until you can wash it off using soap & water indoors, away from the sun. This is because the sap contained in the stem and leaves can react with sunlight damaging the skin.
The sap of Wild Parsnip contains phototoxic compounds that cause burns/blistering when exposed to sunlight, specifically UVA radiation. Specifically, a chemical compound known as phenylpropanoid, which contains linear furocoumarins (LFCs), will react when exposed to UVA radiation between 320-400 nm.[1][5] This furocoumarins interact with oxygen causing acute damage to cell membranes on the skin, resulting in blisters, cell death, and edema.
Symptoms of Wild Parsnip burn
If one comes in contact with the sap that is subsequently exposed to sunlight, blisters and a rash will begin to form over the course of 24 hours. Known as photodermatitis, the rash may itch slightly, but will mostly be painful. Typically the blisters will be gone within one week, but darkening of the skin (hyperpigmentation) will last up to six months.[5]
Treatment
Ice packs can be used to try to relieve pain, as well as hydrocortisone topical steroid creams. If severe, one may take over the counter ibuprofen or acetaminophen for pain relief after consulting with a doctor.
Misdiagnosis
Unfortunately Wild Parsnip isn’t the only plant one may encounter that can cause a rash. The symptoms resemble Poison Ivy or Poison Oak rashes, however rashes associated with these plants primarily itch, whereas Wild Parsnip poisoning will mostly be painful.
What do you do after touching Wild Parsnip?
If you come in contact with Wild Parsnip, quickly assess if there was sap present. If no sap was present, and the leaves and stem are in-tact then it is likely that you will be ok with no effect. If however the sap has gotten onto your skin, then you must take action. The key being to keep the affected area out of sunlight.
First, cover the effected skin so that no sunlight can shine on it. Next, get indoors and wash the effected area with soap and water several times. Then, for the rest of the day keep that effected skin out of sunlight.
How Wild Parsnip is harmful to the environment
Wild Parsnip has the ability (and often does) spread voraciously in disturbed areas, displacing native vegetation which reduces habitat for wildlife. Although the plant does provide nectar and manages to host one butterfly caterpillar, overall it eliminates other species that can provide food/cover to a larger variety of species.
Wild Parsnip Identification / Characteristics
I’m going to be very direct here and tell you the fastest way to identify blooming Wild Parsnip. Look for flat-top clusters of yellow flowers in very late Spring to mid-Summer. That is how you find this plant!
The image above is a great example of numerous small clusters (umbels) of individual flowers. The clusters are formed into a ‘flat-top’ structure that will rise above the surrounding vegetation. Learn this form, and in no time you will be able to identify Wild Parsnip at 60 miles-per-hour down a gravel road in the Midwest!
Lifecycle of Wild Parsnip
The lifecycle of Wild Parsnip is that of a biennial. The first year leaves will form but no tall stalk, and all energy will go toward developing the thick, fleshy taproot. The second year a stalk will shoot up 4-7′ tall, topped with flat-top clusters (umbels) of small yellow flowers.[1]
By late summer, seed heads will form where flowers were, each seed head containing a single seed. At this point, the plant will die and decompose, but new seedlings are likely to emerge the following Spring and the process starts anew.
Stalk
The stalk of Wild Parsnip is smooth, angled in shape, and has ridges/furrows running lengthwise. It is generally green in color and will branch in the upper third. These stems terminate in flowers.[1]
Leaves
Compound leaves are alternate on the stalk and 6″ wide by up to 18″ long in the lower portion with long stems, and smaller in the upper portion. They are generally light to dark green in color. Individual leaflets are roughly 2″ wide by 3″ long, coarsely serrated, lobed, and ovate or elliptic in shape.[1][2]
Flower
Each stem terminates in compound umbels of small yellow flowers. These umbels arrange themselves in a ‘flat-top’ appearance. And individual flower is very tiny, 1/16″-1/8″ diameter with 5 yellow petals surrounding a green nectar source.[1]
Blooming generally starts in late spring and extends well into Summer for up to 8 weeks. About one month after blooming each flower is replaced by a seed capsule that has one seed. Seeds are thing and are distributed somewhat by wind or by birds.[1][2]
Root
The root system of Wild Parsnip is a thick fleshy taproot. The root of first year plants can be eaten. [1]
Look a likes of Wild Parsnip
Below I’m going to show comparisons of Wild Parsnip to some common look-a-likes. Please note that if you are encountering a plant in your garden that you suspect is Wild Parsnip, wear protective gloves to ensure you don’t get any sap on your skin when you remove it. In fact all of these plants with the exception of Golden Alexander have sap that can irritate your skin. And some are downright toxic and dangerous to ingest, such as Hemlock.
Cow Parsnip vs Wild Parsnip
Wild Parsnip will differ from Cow Parsnip in that the leaves of Wild Parsnip are not lobed, and Wild Parsnip will have yellow flowers – not white flowers like Cow Parsnip does.
Golden Alexander vs Wild Parsnip
The flowers of Golden Alexander look very similar to Wild Parsnip, but Golden Alexander will bloom in Spring very early (typically April-May for zone 6), while Wild Parsnip will not bloom until Summer. Also the leaves are quite different, with Golden Alexander leaves being more narrow and more finely serrated.
Giant Hogweed vs Wild Parsnip
There are several primary differences between Hogweed and Wild Parsnip. First, Giant Hogweed is huge, reaching heights of 7-14′ tall. The leaves are quite different in that Hogweed has sharp pointed and deep lobes (in addition to being much bigger). Finally, Hogweed has white flowers, not yellow flowers.
Note that both Hogweed and Wild Parsnip can harm your skin or eyes, so don’t touch without proper protective equipment.
Poison Hemlock vs Wild Parsnip
To compare Poison Hemlock and Wild Parsnip, first we can look to the flowers as Poison Hemlock has white blooms while Wild Parsnip is yellow. Next we can see that the leaves of Poison Hemlock are compound, just like Wild Parsnip, however the leaflets are smaller and more ornate. Also (not shown) Poison Hemlock will have irregular purple splotches all over the stalk.
Queen Anne’s Lace vs Wild Parsnip
Queen Anne’s Lace blooms white flowers the same time as Wild Parsnip (Summer). But the blooms of Queen Anne’s Lace are much more densely packed. The leaves of Queen Anne’s Lace are compound but very thin when compared to the wide leaflets on Wild Parsnip’s compound leaves.
Water Hemlock vs Wild Parsnip
Water Hemlock differs from Wild Parsnip in that the blooms are white, and the compound leaves are very ornate or frilly as they have more & deeper lobes. Looking at the image side by side below it is very easy to differentiate these two species.
How to control Wild Parsnip
Controlling Wild Parsnip successfully can generally done one of two ways. Either mechanical control that removes or severs the root, aka digging. Or, using herbicides against Wild Parsnip.
No matter what type of control you prefer, make sure you wear long pants, sleeves, and gloves to prevent contact with the sap.
Mechanical control of Wild Parsnip
Mechanical control works best on isolated or small populations. Due to the large number of seeds a plant produces, it is important to try to prevent a major infestation rather than controlling one.
For plants that haven’t bloomed, or are just starting to bloom, you can dig, pull, or stab/sever the root about 2″ below the soil to kill the plant.[1] A spade, or narrow spade works great in moist soil for this task. If it is flowering though, you must cut off the flowers and bag them. I am speaking from personal experience – a cut plant has much stored energy and may be able to last long enough to form seeds. Don’t take this risk, cut and bag those seed heads.
For plants that have bloomed, but haven’t seed heads are not forming can be mowed. If you see the green seed heads, you should cut/remove them. However, new shoots may emerge necessitating mowing a second time. [2]
If seed heads have formed on any plant, then it must be removed and disposed of before killing the plant. Cut the seed head off and place into a plastic bag. Leave the bag in direct sun for one week to kill the seeds, or burn the seed heads (following all local burning regulations).
Chemical control of Wild Parsnip
Before I describe the chemical control of Wild Parsnip, please note that given enough time, native species should overtake it. So, care must be taken to only use herbicide on the target plants, and not widely spray herbicides.[1]
But general herbicides such as 2-4-D and glyphosate can be used to kill Wild Parsnip in the basal rosette stage, and glyphosate works on flowering adults.[1] It is best done with a hand sprayer in late fall when native species are dormant to avoid killing non-target species. If plants are sending up stalks, then selective targeting can be done as long as all directions on the herbicide are followed and care is taken to avoid spraying of non-target species. [2][6]
Below is an image of what first year Wild Parsnip looks like. You need to quickly identify the basal leaf rosette, and then either dig out or carefully apply herbicide to the leaves, taking care to not harm surrounding non-target plants. If you can wait until Autumn, most native species will go dormant while Wild Parsnip will still be actively growing. This is the best time to apply herbicide, as the parsnip will absorb the chemicals while the non-target natives will not as they are dormant.
Growing Conditions of Wild Parsnip
Natural Habitat
Wild Parsnip is highly adaptable in it’s growing conditions in that as long as it gets at least a few hours of sun, and doesn’t dry out it should be able to grow. For climate, it can grow from zones 2 through 9! (Zone 2!!!) This makes it highly invasive throughout the United States and Canada, readily invading abandoned fields and pastures, roadsides, disturbed areas, and even abandoned lots in towns.
Sunlight requirements
Wild Parsnip will grow well in full or partial sunlight. The more sun it receives, the taller and showier the flowers will be.
Water requirements
Wild Parsnip prefers moist to medium-moist conditions in soil that drains well. Although it is quite adaptable and is known to grow in compacted soils, even clay.
Soil requirements
For texture, the preference is loamy soil containing organic matter. But this plant is really quite weedy and easily colonizes disturbed areas of seemingly any fertility.
How Wild Parsnip spreads
Wild Parsnip spreads by seed from either the wind blowing seeds or bird droppings. It is really quite prolific, although the seeds do not retain viability much more than one year.[7]
How to grow Wild Parsnip from seed
I absolutely do not endorse nor recommend you grow this plant for edible purposes due to it’s potential to spread. If one wishes too for food, then you should act responsibly and bag the seed heads to prevent birds from ingesting and spreading the plant far and wide.
Wild Parsnip seeds require no pretreatment and can be sown 1/2″ deep (12 mm) after last frost, once soil temperatures reach 55 degrees Fahrenheit (13C). Germination should occur within 2-3 weeks. [7]
As a biennial, Wild Parsnip will bloom the second year. The roots can stay in the soil all Winter long, and can be dug up as you wish to eat them.
Wildlife, Pests and Diseases that effect Wild Parsnip
Pollinators
Wild Parsnip flowers produce much nectar that attracts a huge variety of pollinators. Despite being an invasive species, there is a huge number of pollinators who have been documented visiting Wild Parsnip. Charles Robertson recorded 298 different pollinator species feeding on nectar from Wild Parsnip.[8] Pollinating flies, wasps, beetles, and ants all will visit to collect the nectar.
And although Wild Parsnip is a net negative for the North American ecosystem, it does host Black Swallowtail caterpillars.[9]
Birds
Upland birds are known to eat the seeds.[1] I’ve personally heard from landowners that birds consume and spread the seed, the result is the rapid speed at which this plant can colonize areas at great distances.
Dogs and cats
Although I had never heard of any dog or cat being poisoned or experiencing adverse symptoms from Wild Parsnip, I nonetheless heavily researched this topic. I was unable to locate any record (medical or anecdotal) that connected dog/cat poisoning to Wild Parsnip. Still, based on the other reports of livestock and horses, it is best to exercise caution and keep pets away from Wild Parsnip.
Cattle and livestock / agriculture effect
Ingestion of Wild Parsnip can result in infertility and reduced weight of livestock. The presence of Wild Parsnip in fields can harm the ability to sell various crops such as hay and oats.[10]
Cattle have been fed Wild Parsnip and no effect was noticed, and all vitals were within the normal range. While the same study also found that most goats had minimal effect. [11]
Horses
Horses who ingest Wild Parsnip can be effected negatively in several ways. Over time horses have been documented to have similar injury as humans, in the form of photodermatitis, primarily on the smooth skin around the nose and mouth.[11] In addition to photosensitivty, ocular injury was documented in one study[12]. Based on these results, horses should avoid grazing on Wild Parsnip or eating hay that contains Wild Parsnip.
Uses of Wild Parsnip
Native American uses
Although not native to North America, several Tribes began using the Parsnip not long after it was introduced in the early 1600’s. Some Tribes such as the Cherokee, Iriquois, and Paiute used the plant medicinally. While others thought the root to be poisonous in large amounts such as the Objibwa and Potawatomi. [13]
Edible
Rich in vitamin C, first year taproots of Wild Parsnip are edible and have been used as a food for hundreds (if not thousands) of years. Native to Eurasia, Wild Parsnip root can be boiled, used as a substitute for potatoes, and can be roasted. The sugars will caramelize providing a distinctive sweet flavor. [1][14] Although it is a member of the carrot family, it is not eaten raw.[15]
Final Thoughts
Wild Parsnip is a very aggressive non-native species that rapidly colonizes disturbed areas, abandoned fields, and railroad tracks, etc. It displaces native flora, reducing the amount of host plants for pollinators. At the same time, the fact that nearly 300 pollinators have been documented visiting the plant, plus the fact that it hosts Black Swallowtail butterflies can’t be ignored. This non-native species does provide some value to a wide variety of species, even if it is only nectar.
While many insects make use of this plant for the aforementioned nectar, only one species actually uses it for hosting it’s caterpillars. Considering how invasive Wild Parsnip is….it displaces so many other plants that would thrive in similar growing conditions. That alone means that many species are robbed of their host plants that are out-competed by Wild Parsnip.
For these reasons, we should try to eradicate this invasive species when possible, even though it is established at this point. For your local property or parks, try to safely remove them without getting the sap on your skin, and know that you are doing a good dead for the local pollinator community.
Read more about invasive plants here
References:
[1] – Cain, Nancy, et al. “The biology of Canadian weeds. 144. Pastinaca sativa L.” Canadian Journal of Plant Science 90.2 (2010): 217-240.
[2] – Kennay, Jil, Fell, George. ‘Wild Parsnip Pastinaca sativa L.’ Natural Lands Institute, Rockford, Illinois. Accessed 03FEB2023.
[3] – Pastinaca sativa L. wild parsnip. USDA, NRCS, 2023. Accessed 03FEB2023.
[4] – Pastinaca sativa L. wild parsnip, USDA, NRCS. 2023. The PLANTS Database (http://plants.usda.gov, 3 February 2023). National Plant Data Team, Greensboro, NC 27401-4901 USA.
[5] – Walling, Abigail L., and Hobart W. Walling. “Phytophotodermatitis induced by wild parsnip.” Dermatology online journal 24.2 (2018).
[6] – Tomkins, D. J., and W. F. Grant. “Monitoring natural vegetation for herbicide-induced chromosomal aberrations.” Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 36.1 (1976): 73-83.
[7] – Julie Thompson-Adolf. Starting And Saving Seeds. Quarto Publishing Group, 2018, pp.159
[8] – Robertson, Charles. “Flowers and insects; lists of visitors of four hundred and fifty-three flowers.” (1928).
[9] – Iftner, David C. Butterflies and skippers of Ohio, Columbus, Ohio : College of Biological Sciences, Ohio State University, 1992, pp.212
[10] – Laxton, Dayna. “Managing for Invasive Species.” Drainage Engineers Conference. 2019.
[11] – Stegelmeier, Bryan L., et al. “Wild parsnip (Pastinaca sativa)-induced photosensitization.” Toxicon 167 (2019): 60-66.
[12] – Winter, Judith C., et al. “Photodermatitis and ocular changes in nine horses after ingestion of wild parsnip (pastinaca sativa).” BMC Veterinary Research 18.1 (2022): 80.
[13] – Pastinaca sativa L. Wild Parsnip. North American Ethnobotany Database. Accessed 03FEB2023.
[14] – Sutcliffe, Theodora, 1001 foods you must taste before you die. London : Cassell Illustrated, 2008, pp.960
[15] – Kenneth F. Kiple. The Cambridge World History Of Food (v 1+ 2), Cambridge University Press, 2000, pp.2153
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