Thunderwood, Poison Sumac, Poison Dogwood, Poison Elderberry, Swamp Sumac
The poison sumac is a unique and interesting native shrub to the wetlands of North America. This shrub is related to poison ivies and poison oaks and not sumac, because of its common rash-causing agent, urushiol. The leaves, bark, fruit and flowers all contain this agent, making it poisonous. When burned, the smoke from the plant is deadly and will cause the insides of a person's lungs to swell. Poison sumac is relatively rare only growing in very wet and flooded soil such as swamp although typically these shrubs will be grouped together. Some of the characteristics that set the poison sumac apart from many similar-looking shrubs include the red colour along the stem connecting leaflets, grey fruits about 0.5 cm in size that hang downwards, light green flowers in loose clusters 10 - 15 cm long. Both male and female flowers grow on the same plant. These flowers require bees for pollination. The overall shape is commonly skinny and sparse. The leaves are tear-shaped with a smooth edge. However, the location of this shrub will be a strong indication that the poison sumac loves extremely wet soil, and is able to grow in the middle of swamps where other hardy shrubs will fail. The wood of this plant is soft, light weight, and is a slow grower. Poison sumac has been documented to be used as a medicine. Although it is one of the most poisonous plants, it has been used to treat health problems such as fever, ulcers and asthma. Other uses include dye, ink, miscellany, mordant, oil and varnish. Anyone wanting to handle poison sumac should only do so under supervision of an experienced practitioner.
|USDA Hardiness Zone
|3 - 7
|Canadian Hardiness Zone
|2 - 8
|RHS Hardiness Zone
|3 - 5 m
|9 - 12 m
|Deciduous, medium sized shrub with tear-shaped leaves. It has clusters of grey fruits, red along the stem connecting the leaflets, and very small greenish flowers in early summer. Grows in swampy situations. The plant contains the toxic substance urushiol.
|Vertical, sparse small tree or a tall shrub.
|Red colour along the stem connecting leaflets, grey fruit about 0.5 cm in size that hang downwards. The flowers are light green and are arranged in loose clusters 10 - 15 cm long. Both male and female flowers grow on the same plant.
|The poison sumac tolerates wet conditions, so its habitat does not vary significantly. It can be found only in swamps, wetlands, peatland and moist woodland.
|Rough, light grey, and becomes darker with age with pronounced, large lenticels.
|Flower/Leaf Bud Description
|Has glabrous reddish-coloured buds that are conical shaped and about 0.5 - 1 cm long.
|Each pinnate leaf has 7 - 13 leaflets. Each leaf is 5 - 10 cm arranged alternately or opposite each other. New spring leaves may be orange before turning green and back to orange and red in the autumn.
|Tiny light green or yellow-green flowers in loose clusters 10 - 15 cm long, toxic.
|Clusters of grey fruit about 0.5 cm in size that hang downwards.
|Some orange and reds when leaves when they emerge in the spring and again in the autumn. Flowers are yellow to green while the fruit and new bark is all a similar shade of light grey.
|Ethnobotanical Uses (Disclaimer)
|Leaves, bark, fruit and flowers are TOXIC. These can be made into an oil used to treat ulcers and some diseases. Other uses include dye, ink, miscellany, mordant, oil and varnish.