“I fear I am a little impatient of the school of gardening that encourages the selection of plants merely as artistic furniture, chosen for colour only, like ribbons or embroidery silk. I feel sorry for plants that are obliged to make a struggle for life in uncongenial situations, because their owner wishes all things of those shades of pink, blue or orange to fit in next to the grey or crimson planting.”
Edward Augustus Bowles My Garden in Spring (1914)
Garden Lore: arum lilies
Arum lilies are something of a scourge in this country. These are the remains of a selected white splashed-green flowered form called ‘Green Goddess’. I have just done what I hope is the final clean up in my eradication efforts. You can imagine the hollow laugh of disbelief from Mark when I informed him that ‘Green Goddess’ has an Award of Merit from Britain’s prestigious Royal Horticultural Society. It is clearly not a weed there, no sirree.
The common weedy arum here is from South Africa and is Zantedeschia aethiopica, although Z. italicum is also a problem. The issue is that these plants just do too well here. They are tolerant of a very wide range of conditions and, being toxic, stock won’t touch them so they can multiply even on grazed land. Not only do they spread by seed but you can see from the root system why they can be difficult to eradicate. The rhizome below ground has numerous offsets and every one has the potential to grow to a separate plant.
I eradicated by digging carefully and thoroughly gathering all the baby offsets. Don’t risk composting them. Either dry and then burn them or put them out in the rubbish for deep burial at landfill. Never, ever dump them on the roadside. I have just done what I hope is the final follow-up to root out the remaining stragglers after 3 years. If you want to go the chemical way, the Weedbusters website recommends metsulforon-methyl with glyphosate and penetrant (to make it stick). Or Escort is what Mark recommends – that is the metsulforon-methyl bit.
The smaller growing, coloured zantedeschias that are often known as calla lilies are generally derived from different species and do not show the same weedy inclination, being prized as cut flowers and making excellent garden plants. However, they are apparently all equally toxic so take care when handling them as their sap can burn.
First published in the Waikato Times and reprinted here with their permission.