Download MSdoc - Stevens County

Poison ivy
Rhus radicans L. aka Rhus toxicodendren
Sumac Family
Key identifying traits





Leaves are alternate, compound in groups of three,
somewhat shiny and often drooping
Flowers are small and yellowish-green; bloom time is
generally in May and June
The inconspicuous flowers are composed of 5 sepals, 5
petals , 5 stamens and a single pistil
Fruit is a globe-shaped, creamy-white, waxy berry;
each pod has one round, white & gray striped seed
Leaves turn bright red in the fall
“Leaves of three, let them be”
Biology and ecology
 It is a perennial native of North America
 Reproduces by seed, rhizomes, and rooting of the
stem nodes; birds eat the berries and spread seed
 Can grow as either a shrub or a climbing vine
 It thrives under a wide variety of conditions
 Contact with the plant can cause severe itching; skin
becomes red and blistered within 24 hours
 Toxic properties and rhizomes make control difficult
 Often confused with Poison Oak, a similar species
usually found on the west side of the state
immature fruit
Control
Prevention – Learn to identify plants; know your property;
don’t let birds fly over your property
Biological – No known biological agents yet
Cultural – Good vegetative cover helps but does not
prevent establishment or spread
Mechanical – Cutting will not achieve control due to the
underground root system; burning is dangerous as it
releases the toxins into the air; repeated cultivation can
be effective
Chemical – Several effective but may require repeat
treatments; timing depends on chemical used
Photo courtesy Agriculture & Agri-Food of
Canada
Where found – Found in many locations throughout Stevens County, close to water bodies
such as lakes and scattered along the Columbia River. Also along many railroad rights-of-way.
Stevens County Noxious Weed Control Board, January 2006