Pretty but noxious, Italian Arum is spreading

Italian Arum is on the rise in San Juan County, especially on Lopez Island - including the Fisherman Bay Spit Preserve. This class C noxious weed is invasive, toxic and difficult to control.

According to the state Noxious Weed Board: Italian arum is poisonous, destroys riparian and other sensitive habitats, and is extremely difficult to control. It has escaped in several counties in western Washington and is invading more areas rapidly. Spreading in yard debris and contaminated compost, it may also escape from gardens into natural areas.

Any part of the plant can cause severe skin irritation, illness, or death to people, livestock, and wildlife. In open areas, it can shade out small native plants and keep other plants from establishing. Its tubers multiply yearly to create new plants, and birds spread the seeds. 

Identification Italian arum (Arum italicum), also called “Lords-and-Ladies,” “Italian lily,” and “Cuckoo’s pint” is an ornamental groundcover to 1.5 feet tall. Leaves emerge from tuberous roots in fall, stay green all winter, and die back in summer.

• Arrowhead-shaped leaves can be all green or have cream-colored or silver-gray veins, purple splotches, or speckles.

• Flowers (April–June) are an unpleasant-smelling, yellowish, fingerlike spadix with a pale hood, or spathe.

• Fruits (August–September) are orange-red and cluster tightly in oblong spikes.

• Thick underground tubers store much of the plant’s energy and water underground, which is why the tops regrow so easily when cut or mowed. One way the plant reproduces is by producing buds, called “daughter tubers,” which detach and form new plants.

To help stop the invasion:

Do not plant it

Remove and dispose of Arum berries. Use gloves, place in a plastic bag, dispose in garbage, not compost

Dig up and dispose of the plants and its tubers. Use gloves, place in a plastic bag, dispose in garbage, not compost

Identify locations in the islands and notify the San Juan County Noxious Weed Control Board at [email protected]

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