poison sumac

(Toxicodendron vernix)

Conservation Status
poison sumac
Photo by Jordan Wilson
  IUCN Red List

LC - Least Concern


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status

OBL - Obligate wetland

  Northcentral & Northeast

OBL - Obligate wetland


Poison sumac is a fast-growing, short-lived, deciduous, tall shrub or very small tree. It can be 10 to 25 tall and up to 6 in diameter at breast height, though in Minnesota it is usually no more than 15 in height and 2 in diameter.

The trunk is slender and is often branched near the base, and there are often vegetative sprouts at the base. The crown is small and rounded, with just a few wide-spreading branches.

The bark is thin, light gray, and smooth or shallowly fissured.

The twigs are moderately stout and orangish-brown or yellowish-brown. They are covered with conspicuous dark dots and splotches, and have numerous prominent, horizontal pores (lenticels). The leaf scars are large and shield-shaped, and has a number of scattered bundle scars. The terminal buds are broadly cone-shaped, to ¾ long, and are covered with downy scales. When broken or cut, the twigs exude a dark sap.

The leaves are deciduous, alternate, 6 to 12 long, and pinnately divided into 7 to 13 leaflets. They are on ¾ to 3½ long leaf stalks (petioles). The petiole and the central axis of the leaf (rachis) are red or yellowish-red. The rachis is hairless. The lateral leaflets are stalkless of on very short stalks. The terminal leaflet is on a to 1¼ long stalk (petiolule).

The leaflets are oblong to inversely egg-shaped or elliptic, 2 to 4 long, and 1 to 1¾ wide. They are wedge shaped at the base at an angle less than 90° and taper abruptly to a long point at the tip with concave sides along the tip. The upper surface is dark green, shiny, and hairless. The lower surface is pale green and hairless. The margins are untoothed. In autumn the leaves turn orange or red.

Male and female flowers are usually borne on separate plants. They appear in early to late June after the leaves have developed. The inflorescence is a loose, branched cluster (panicle), up to 8 long and 4 wide, rising from the leaf axils of first-year twigs. The flower stalks may be hairless or covered with short hairs. The panicle is more or less erect in flower, conspicuously drooping in fruit.

Individual flowers are about long. There are 5 sepals, 5 petals, 5 stamens on the male flower, and 1 style on the female flower. The sepals are green to cream-colored, united at the base, and divided into 5 teeth at the tip. The petals are greenish-yellow and 1 16 to long. The stamens have white stems (filaments) and yellow anthers and protrude beyond the petals. The style has 3 lobes.

The fruit is an almost spherical, to 3 16 in diameter, fleshy, berry-like drupe. It is green and shiny at first, turning white or ivory-colored when ripe. It matures in late August to late September and persists on the plant throughout the winter.




10 to 15


Flower Color




Similar Species


Wet. Mostly swamps but also marshes and wet meadows. Shade. Saturated, sandy or peaty soils.




Early to late June


Pests and Diseases






The sap of poison sumac contains the allergenic urushiol. Urushiol is not a single chemical but a complex of five chemicals called alkylcatechols.

Several exposures to the substance may be necessary to impart sensitivity. Research has shown that 85% of all people will develop contact dermatitis after adequate exposure. It usually takes 12 to 48 hours for a rash to develop on a previously sensitized person. In some individuals, a single exposure will cause a reaction. In these individuals, the rash will develop in seven to ten days.

The lesions last 14 to 20 days. Rashes do not spread and are not contagious. Treatment can dry the blisters, reduce swelling, and relieve itching, but will not speed healing.

Contact with the outer surface on an undamaged plant should not cause an allergic reaction unless there is residual urushiol present from a previous injury to the plant or a nearby plant. Contact with a torn leaf, broken or damaged stem or rhizome, or black spot will cause a reaction in those sensitized to urushiol.


Distribution Map



2, 3, 4, 5, 8, 24, 28, 29, 30.








Uncommon in Minnesota

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Rosanae  


Sapindales (soapberries, cashews, mahoganies, and allies)  


Anacardiaceae (cashews)  
  Subfamily Anacardioideae (cashews, sumacs, and allies)  


Toxicodendron (poison ivies and oaks)  

Subordinate Taxa






Rhus vernix

Rhus vernicifera


Common Names





poison sumac














The upper angle where a branch, stem, leaf stalk, or vein diverges.


Bundle scar

Tiny raised area within a leaf scar, formed from the broken end of a vascular bundle.



A fleshy fruit with usually a single hard, stone-like core, like a cherry or peach; a stone fruit.



On plants: The thread-like stalk of a stamen which supports the anther. On Lepidoptera: One of a pair of long, thin, fleshy extensions extending from the thorax, and sometimes also from the abdomen, of a caterpillar.



A corky, round or stripe-like, usually raised, pore-like opening in bark that allows for gas exchange.



A pyramidal inflorescence with a main stem and branches. Flowers on the lower, longer branches mature earlier than those on the shorter, upper ones.



On plants: The stalk of a leaf blade or a compound leaf that attaches it to the stem. On ants and wasps: The constricted first one or two segments of the rear part of the body.



The stalk of a leaflet blade on a compound leaf.



On a compound leaf, having the leaflets arranged on opposite sides of a common stalk. On a bryophyte, having branches evenly arranged on opposite sides of a stem.



The main axis of a compound leaf, appearing as an extension of the leaf stalk; the main axis of an inflorescence.

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Jordan Wilson

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Jaxon Lane

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MinnesotaSeasons.com Photos





winter twigs, poison sumac
  winter twigs, poison sumac  

Walpole, MA 2/7/13




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Other Videos
  Poison sumac Identification (Toxicodendron vernix)
Peter Caine Dog Training

Published on Jul 2, 2017

Poison Sumac Toxicodendron vernix, commonly known as poison sumac, is a woody shrub or small tree growing to 9 m tall. It was previously known as Rhus vernix. This plant is also known as thunderwood

  Casting Call - Poison Sumac Plant (Toxicodendron vernix)

Published on Sep 8, 2014

When I made the shelter video I has accidentally came into contact with poison sumac. This video explains what the plant is, how to identify it, what happens if you come into contact with it, how you can avoid getting the rash/blisters, and what can be done to control the symptoms.

  Wild Moments: Poison sumac often misidentified

Published on Jun 29, 2012

  What does Poison Sumac Look Like?

Published on Jun 9, 2015

  Poison Sumac Identification
Ditch The Itch

Published on Jun 12, 2017

Wetlands in Western Michigan. A very good video of Poison Sumac Identification. I am a licensed pesticide applicator in Michigan, and I specialize in noxious plants (Poison Ivy, Poison Sumac)




Visitor Sightings

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  Jordan Wilson

Location: Boot Lake SNA

poison sumac  
  Brien Larcom

Location: Willmar, MN

  Jaxon Lane

Location: Tamarack Nature Center

poison sumac  
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Created: 10/23/2018

Last Updated:

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