Invasive Cuckoo's Pint

Linda Ellis* sent a report of an new alien invasive species at Valley Water Mill.  It is called Italian arum or Italian lords-and-ladies (also orange candleflower, cuckoo's pint....go figure). Formally named Arum italicum, it is native to the Mediterranean, Great Britain and scattered European and island locations. It has been popular with gardeners as a companion plant in hosta gardens as it blossoms as the hostas fade.

Cuckoo's Pint at Valley Water Mill - Linda Ellis

If this plant looks vaguely familiar, you probably are thinking of our native Jack-in-the-pulpit, Arisaema tryphyllum. Fold down the hood and you can see the similarity. Both plants are arums and all parts of them are poisonous.

Spadix and spathe - MoBotGarden

Jack-in the pulpit

Missouribotanicalgarden.org describes them in technical terms.

"Each flower consists of (1) an erect, finger-like spadix covered with minute, creamy white flowers and (2) a large, sheath-like, light green spathe (bract) which subtends and partially envelops the spadix like a hood. Flowers produced in spring. Arrowhead-shaped, long-petioled, glossy grayish-green leaves with pale green midribs are 8-12" long. After bloom, the leaves and spathe die back leaving only the thick spadix which develops attractive, bright orange-red berries in summer." 

Arum italicum has an interesting characteristic.  It and a few other Arum species are thermogenic.  A tiny thermometer placed on the upper free portion of the spadix may show a temperature of 6 to 10 degrees Celsius above the surrounding air.  In one study it even registered 17 degrees higher, one hot little number.  This apparently only occurs in brief periods while flowering.

Arum italicum is a good example of an early escapee. It has been reported one time before in Greene County in 2010.  The map at Invasiveplantatlas.org suggests that it is quite early in its spread and only time will tell if it becomes a major problem but anytime an exotic plant starts to show up where it wasn't planted it becomes a concern.

Not only is it bad for our native plants but it is also a risk to humans.  All parts of the plant are poisonous and eating it can be fatal.  Gloves are advisable in removing it as contact with this plant can cause skin irritation.  Oregon has a lot of experience with it and here is their advice;

"Getting rid of Italian arum is a pain. Even professional land managers struggle with it, which is why early control is very important.  Herbicides don't work well and digging it up is a lot of work. Manual removal is only recommended on small patches, because soil disturbance tends to increase the spread of the plant.  All plant parts and nearby soil should be placed in a bag and disposed of in the trash -- not your yard waste bin or home compost. Infested sites should be checked weekly to stay on top of any new sprouts."

This is a species of concern.  We are early in its invasion.....we think.  Like many escapees (think Callary pear), it is best to attack before we are faced with another ecological crisis.

*Mike Kromrey and Rob Hunt saw a plant they didn't recognize and sent the photographs to Linda Ellis.  Curiosity pays..
** The Corpse Flower that was at the Botanical Center in 2010 is also thermogenic.  See this link for details.