Garden Lore

“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)

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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.

Garden lore

“What is a weed? I have heard it said that there are sixty definitions. For me, a weed is a plant out of place.”

Donald Culross Peattie, (1896 -1964).

Weed plants
After my recent faux pas with Lilium formasanum, I was contacted by Carolyn Lewis, the national coordinator of Weedbusters, an organisation with support from many interested parties, dedicated to raising awareness of the problem weeds in this country. Too many of these are garden escapes and gardeners need to take some responsibility for unleashing vegetable time bombs. The website http://www.weedbusters.org.nz gives extensive information on individual weeds including how to eradicate each species in your area and useful suggestions of alternative plants to use instead.

Weedbusters are not covering the plants included in the National Pest Plant Accord (which are the banned ones) although there is a link through to the Ministry for Primary Industries section on these agreed pests. Some of the inclusions surprise me (Bartelttina sordida for one), others don’t. The arum lily, aristeas and agapanthus are widely recognised as problematic. I would have liked to have seen more information on where these plants are problems (national, regional or specific to just one area) because one region’s weed can be another region’s valued garden plant.

Without becoming too paranoid, take notice of those that seed down too freely or spread rampantly in your domain. If they are popping up all round the place, threatening to invade well beyond their allotted space and choking out other plants, or are extremely difficult to eradicate then you are probably looking at plants with significant weed potential for your conditions. While purists may advocate total eradication, in some cases we choose to manage such plants. We don’t want to be without our campanulata cherries that feed the tuis but we take responsibility for the seedlings and are vigilant weeders. The vegetable garden is not exempt either. We rated strawberry spinach as downright dangerous and went for eradication.

We don’t need more weeds in this country.

First published in the Waikato Times and reprinted here with their permission.