Autumn Invader: Italian arum

Italian arum leaves

Barry Rice, sarracenia.com, Bugwood.org

by Mark Frey, Exotic Plant Management Team Liaison, National Capital Region

The non-native plant Italian arum (Arum italicum), is kind of like an unwelcome night-owl roommate who raids the fridge while everyone sleeps and co-opts shared spaces with their stuff. Literal turf wars can erupt!

Many invasive non-native species like Italian arum have life histories that are somewhat out of sync with native plants. Their off-schedule habits (asynchronous phenologies) can let them take advantage of light when other plants have already shed their leaves and perhaps take in other resources when native species have already shut down.

Italian arum is an extreme example. Like most plants in the region it is active in spring, but what really sets it apart is when it emerges in the fall as other plants are dying back. It goes dormant in colder winters and emerges again in spring, dying back around June. During a mild winter, Italian arum can stay green for all 3 seasons.

When you are out hiking, especially near urban areas, keep an eye out for this interloper. Its dark green leaves can rise up to two feet above the forest floor and often have striking white veins.