A few years ago, I found a plant growing in my garden that I was very happy to have. Its leaves were arrow-shaped and were variegated with dark green and white stripes. When it fruited, it was with orange-red tall spikes. It was very pretty and although I didn’t know what it was, I was willing to let it live in my garden. I didn’t bother to do any research into its growing properties or cultivation needs. I was just happy it was a perennial and I loved seeing it come up every summer and bloom.
And then, as I was walking through the Tillamook County Fair earlier this month, I stopped at the Tillamook County Soil and Water Conservation District booth, I noticed a fact sheet with my orange-spiked plant. Only it wasn’t in the “good plants to have section,” it was one of the SWCD flyers on noxious weeds. Yikes! I took the fact sheet, found a bench, and sat down immediately to read it.
The plant is called Italian Arum (Arum italicum) but has also been commonly called “orange candle flower” or “Italian lords and ladies.” The flowers appear in the spring and look a little like the Jack-in-the-pulpit flowers: long, finger-like and a light yellow. They do have a rather nasty scent. The fruits are the orange-red color and are clustered in tight clumps. Alum was introduced as an ornamental plant and is now naturalizing and becoming a problem as it happily spreads throughout the county.
This is a woodland species that likes the moist and well-shaded environment that we have on the Oregon coast. Once it establishes itself, it spreads from our gardens into the woodlands, becoming more difficult to eradicate once it is in the forest or riparian areas.
A pretty plant that spreads easily from cultivated gardens? Hum. Does that sound familiar? Think Scotch Broom! Arum, too, forms a dense cover in open sites and competes with native plants for the open spaces. Successfully, too. But it has a more sinister property that makes it worth removing from our gardens: it is highly toxic to humans and animals.
All parts of Italian arum are highly poisonous. Handling of the plant or any of its parts can cause severe skin irritation. Ingestion can cause swelling of the mouth and throat that may be followed by breathing difficulties, burning pain and upset stomach. Death may follow. All of this information comes directly from the SWCD fact sheet.
After reading the fact sheet, I went home to do more research and found out that some nurseries are still selling this plant through the mail. Other websites list it as a preferred plant or a plant-of-the month. Don’t be fooled. This is not a plant for a garden that is frequented by children or curious animals!
Controlling this plant is tough but can be done by preventing its spread. Wearing gloves and long sleeves, eliminate the seeds by cutting the seed heads and bagging them for removal in the garbage. Then wash the clothes and gloves in very hot water. Composting does not work! It just gives them a new place to spread. Small patches in home gardens can be carefully dug out, taking care not to break the corms (bulb-like roots) apart as they will divide and spread under the ground. Bag all parts of the plant and dispose of in the trash. Chemicals are less effective because they kill the leaves but not the corms.
Don’t move soil from that area into another part of the garden or into the compost as there is a chance you might have missed a corm or two. Mowing or burning doesn’t do it either, so if you have a large patch, it is best to contact Tillamook County SWCD at 503.842.2848, ext. 103 to ask their advice. As the patches of Arum are identified, the SWCD will offer technical assistance to landowners with infestations. They evaluate each case on an individual basis.
Also, the SWCD acts as the agent for the Tillamook County Weed Control District and they look for help from residents in identifying Italian arum populations in the county. Same phone number and extension if you spot a patch you think needs to be addressed. Thank you to the West Multnomah Soil and Water Conservation District for the use of their photo.
Which brings me to a conclusion that those of us with small children or grandchildren that visit or with cats or dogs, we need to be aware of the plants in our gardens that are toxic. Most of us know about monkshood (Acontium), oleander and castor beans but there are others that we need to know about, too. Watch this column for more information on keeping toxic plants from becoming problematic. But first, I will add Italian arum to that list.