parsnip

Although many of us fondly associate parsnips with a rustic,
home-cooked meal, there is also a wild variety that is
increasingly causing problems as a weed in North America.
The cultivated variety is a subspecies of Pastinaca sativa
(Pastinaca sativa ssp. sativa) and contains lower amounts of
the problematic furanocoumarins than the wild version. Wild
parsnip (Pastinaca sativa L. PAVSA) is an introduced
facultative biennial from Eurasia. It has spread throughout
the United States and southern Canada and is now colonizing
old fields, railroad embankments, roadsides, and waste areas.
Wild parsnip contains furanocoumarins, which deter herbivores from eating its foliage. These compounds can also cause
phytophotodermatitis in humans and livestock, a condition
that results in patches of redness and blisters on the skin when
they come into contact with the sap or ingest parts of the plant
in the presence of sunlight. Few people, including medical
professionals, recognize the plant or associate it with the burns
it causes. Recently, wild parsnip has received increasing
attention as expanding populations have resulted in more
frequent human and livestock contact with the plant. This
article reviews important aspects of the etymology, distribution, history, biology, and management of wild parsnip. A key
objective of this review is to raise awareness of the potential
health problems caused by wild parsnip and to stimulate
research that will lead to effective management of this
increasingly problematic species.

Description
Wild parsnip is a tall, stout, herbaceous plant with a long,
thick, and deep taproot (Gleason and Cronquist 1991) (Figure 1). The plant is most often a biennial, but can behave
as a monocarpic perennial (Baskin and Baskin 1979; Gleason
and Cronquist 1991), thus dying after the production of
flowers and seeds (Kline 1986). The roots can grow to a 1.5-m
depth (Gleason and Cronquist 1991), and are funnel-shaped,
white, aromatic, mucilaginous, sweet, and slightly acrimonius.
The root has been a widely utilized esculent since early times
(Hedrick 1919). Wild parsnip does not reproduce vegetatively
(Hendrix and Trapp 1992). Rosettes grow near the soil
surface and bear alternate, pinnately compound leaves,
approximately 15 cm in length (Lorenzi and Jeffrey 1987).
The plant requires 2 or more years to mature, at which time
plants bolt, form a grooved aerial shoot and flower (Baskin
and Baskin 1979). Lower leaves have longer petioles than the
upper leaves, which are sometimes sessile. Each leaf has 5–15
oblong to ovate leaflets, which are 5–10 cm long and serrate
or lobed (Gleason and Cronquist 1991).
Inflorescences are large, compound, determinate umbels,
approximately 10–20 cm wide. Petals are yellow, usually with
no bracts or bractlets, and sepals are minute or lacking.
Flowers have 15–25 rays of unequal length and an
appendicular axial structure termed the carpophore. Fruits
are schizocarpic, glabrous, elliptic to obovate, strongly
flattened dorsally (Gleason and Cronquist 1991), low-ribbed
(Lorenzi and Jeffrey 1987), and 5–7 mm in length (Gleason

and Cronquist 1991; Lorenzi and Jeffrey 1987). The fruits
contain two mericarps, each with one seed (Hendrix et al.
1991) and consisting largely of tissues of an inferior ovary
(Jackson 1933). Fruits are considered tonic and are said to be
both carminatives, which aid in digestion, and emmenagogues, which induce menstrual flow (French 1971). The ploidy
level of wild parsnip is 2n 5 22 (Gleason and Cronquist
1991). Wild parsnip is andromonoecious, with individual
plants bearing both male and hermaphroditic flowers. The
hermaphroditic flowers are protandrous, going through
a staminate, then a pistillate stage (Nitao and Zangerl
1987), with little or no overlap between the stages (temporal
dioecism), either within or between umbels, thus preventing
cross pollinations between flowers of the same plant (Cruden
and Hermann-Parker 1977).
Many species in the Apiaceae, including wild parsnip, can
cause phytophotodermatitis (PPD) in humans if skin is
exposed to the light-sensitizing sap of the species and
ultraviolet (UV-A 320–380 nm) radiation. The reaction
consists of a burning erythema beginning approximately
24 h after exposure, which may later blister. The inflammatory reaction may be mild enough to go undetected, but can
also cause severe postinflammatory hyperpigmentation lasting
weeks to months. Furanocoumarins (furocoumarins) are the
photosensitizing chemical compounds found in the sap of
wild parsnip and cause the phototoxic reaction (Berenbaum
1995). The sap of the plant is most irritating when the plant is
in flower (Kennay and Fell 1990).
Many members of the Apiaceae, including other weedy
species, such as wild carrot (Daucus carota L.), poison hemlock
(Conium maculatum L.), spotted water hemlock (Cicuta
maculata L.), and giant hogweed (Heracleum mantegazzianum
Sommier and Levier) share similar characteristics with wild
parsnip. Distinguishing features of wild parsnip, however,
include its yellow flowers, pinnately compound stem leaves
that are divided into at least five coarsely-lobed leaflets, and its
distinctive parsnip odor (Alex 1992; Kennay and Fell 1990)
(Figure 1).
Several features help distinguish between species in the
genus Pastinaca (Table 1). Leaves that are simple and glabrous
on both sides, characteristics only of P. lucida, differentiate it
from the other Pastinaca species, which have pinnate leaves
that are hairy on both sides. Other distinguishing characteristics include leaf shape and the degree to which they are
pinnatifid, the presence or absence of bracts and bracteoles,
petal color and hairiness, the number and length of rays, and
the presence or absence of brown veins. P. sativa has once
pinnate leaves that are hairy on both sides, lacks bracts and
bracteoles, has yellow, glabrous or subglabrous petals, equal or
subequal rays, and brown veins. Furthermore, P. sativa ssp.
sativa can be differentiated from other subspecies by close
examination of the stem and the presence of hairs on leaves
(Table 2).
Distribution and Habitat
Wild parsnip is widely distributed in Europe and temperate
Asia, where it originated. It is found in many countries
including Belgium, France, Georgia, Germany, Italy, the

Netherlands, Spain, Ukraine, and the United Kingdom, as
well as Australia, Canada, and the United States (USDA ARS
2006). Wild parsnip is also widely naturalized in China and
Japan (Hiroe 1958), New Zealand (USDA ARS 2006), and
southern Africa and southern South America (USDA ARS
2006). In North America, wild parsnip is predominantly
found in eastern regions, but it is widely naturalized across the
United States. The species is distributed within 45 of the 50
United States (excluding Alabama, Florida, Georgia, Hawaii,
and Mississippi). It is considered a noxious weed in Ohio
(USDA NRCS 2006) and invasive in Kentucky, Nebraska,
Tennessee, and Wisconsin (Haragan 1991; Hoffman and
Kearns 1997; Stubbendieck et al. 1994). Wild parsnip is

present in all of the Canadian provinces except the Northwest
Territories and Nunavut (Darbyshire 2003). It is considered
noxious in parts of Ontario (S. J. Darbyshire, personal
communication), and is abundant in Quebec (Mulligan
1987). Cultivated parsnip (Pastinaca sativa L. ssp. sativa) is
now grown worldwide (Schery 1972).
Wild parsnip is commonly found in waste areas, old fields,
and along roadsides and railroad embankments. It grows best
in rich, alkaline, moist soils, but can survive under poor soil
conditions (Alex 1992; Fernald 1950; Gleason and Cronquist
1991; Schery 1972). Under summer drought conditions of
Oxfordshire, U.K., Sternberg et al. (1999) found that the
growth of wild parsnip plants in an old field increased and the

growth of perennial grasses decreased. This tolerance to
drought by wild parsnip may be due to its deep tap root,
which allows access to water and nutrients from deeper soil
layers (Tutin 1980).

History
Wild parsnip is an introduced plant native to Eurasia
(Gleason and Cronquist 1991; Hedrick 1919; Hiroe 1958).
This weedy species is native to regions between the western
Mediterranean and the Caucasus Mountains (Rubatzky et al.
1999). According to Hedrick (1919), there is some doubt as to
whether plants referred to as Pastinaca were cultivated in early
times and also whether Pastinaca correctly refers to parsnip.
Greek and Roman civilizations reportedly used Pastinaca as
a food source, but they might have also been referring to
carrots, highlighting the confusion in nomenclature between
carrot and parsnip plants among early botanists. The Roman
Emperor Tiberius (42 BC–AD 37) was apparently so fond of
parsnips that he had them delivered to Rome annually from the
Gelduba region on the Rhine in Germany, where they were
thought to be grown to great perfection. Andrews (1958)
clarifies the convoluted nomenclature surrounding the historical use of the word pastinaca and the uncertainty about
whether these plants were cultivated or wild parsnips.
Although parsnip was likely cultivated long before 1542,
when it was recorded in Germany, the root was unknown in
Germany several years earlier in 1536. In 1552, parsnip was
purportedly better known in kitchens than fat and was
consumed especially by the poor (Hedrick 1919). The
cultivated parsnip was widely grown in northern Europe by
the 16th century (Rubatzky et al. 1999). In 1683, the parsnip
was often used in England as a delicate and sweet food and
was probably cultivated. It was observed on Margarita Island,
Venezuela in 1564 and in Peru in 1604. The parsnip, likely
referring to the cultivated subspecies, was introduced into
North America by the earliest colonists and was cultivated in
Virginia in 1609 and in Massachusetts in 1629, and was
considered common by 1630. The species was also cultivated
by Native Americans and was among the crops destroyed by
General Sullivan in western New York in 1779 (Hedrick
1919). The natives used its roots as treatment for sharp pains,
a root poultice on inflammations and sores, and tea in small
quantities for ‘‘female disorders’’ (Foster and Duke 1990). It
is probable that the cultivated parsnip escaped soon after its
introduction in North America and reverted to its wild form.
Distinguishing between the cultivated and wild populations of
parsnip may be difficult, especially because the often-cited
differences in leaf degree of hairiness characteristics do not
appear consistent (S. J. Darbyshire, personal communication).
However, Berenbaum et al. (1984) found the content of
furanocoumarin in seeds differs between cultivated and wild
parsnip plants.