Sometimes, the plants we choose are not suited for their site. It might be too dry, too sunny, or the plant itself just might be a stinker. Such is the case with Italian arum weeds. While attractive and useful in its native range, when brought to certain regions, it will take over and become obnoxiously invasive. Below are some tips on how to kill arum and take back your garden beds.
What are Arum Weeds?
Arum is a broad family of mostly foliage plants. Italian arum is also known as Lord’s and Lady’s or Orange Candle flower. It is an attractive foliage plant from Europe that quickly colonizes introduced ranges. It spreads by both bulb and seed and reproduces rapidly. In many areas, it is classified as a toxic weed. Managing arum plants is challenging but possible.
Most arums are pleasant and well-mannered plants, but Italian arum are pests. The plant looks a bit like a calla lily when not in bloom and has arrow-shaped, glossy green leaves. It can grow up to one and a half feet (46 cm.) tall.
In spring, tiny white flowers embraced by a bract appear, followed by clusters of orange red berries. The leaves will die back in cooler climates but may remain in warm areas. All parts of the plant are poisonous and even contact with the sap can cause skin irritation.
Managing Arum Plants
Italian arum control can occur with manual techniques, but all parts of the plant must be removed since even a small bulblet can sprout and grow a new plant. Control by digging is most effective for small invasions. All parts of the plant must be removed from the soil or an even worse infestation could occur.
Sifting the soil can help find all the little bits. All parts must be bagged and disposed of, not placed in the compost bin where the plant could take hold. If you want some of the plants to remain, cut the berries off in August before it seeds.
How to Kill Arum Weeds
Controlling Italian arum with chemicals is not always affective initially. The herbicide will kill the foliage making it appear to be dead, but the following spring the bulbs will re-sprout. Glyphosate and Imazapyr will kill the leaves but won’t touch the underground structures.
A trial by Washington State University determined that herbicides with three percent glyphosate with sulfometuron resulted in no top growth. Other herbicides may provide effective control in top growth but must be followed up in successive years to finally kill the bulbs.
Note: Any recommendations pertaining to the use of chemicals are for informational purposes only. Specific brand names or commercial products or services does not imply endorsement. Chemical control should only be used as a last resort, as organic approaches are safer and environmentally friendly.