WEEDS IN NEW ZEALAND

Press, Volume XCIV, Issue 28128, 17 November 1956, Page 6

WEEDS IN NEW ZEALAND

MANY HAD ORIGIN IN GARDENS

ADDRESS TO INSTITUTE OF HORTICULTURE

The harmful effect of discarding some horticultural species from gardens was the subject of an address to the annual meeting of the Canterbury District Council of the Royal New Zealand Institute of Horticulture by Mr A. J. Healey, assistant director of the Botany Division of the Department of Scientific and Industrial Research. “Many* people never think that the horticultural plants which they lavish care on may be wolves in sheep’s clothing,” said Mr Healey. “A very large number of our national weeds owe their origin to horticultural activity.

Mr Healey said that when Darwin visited New Zealand in 1835 he saw at two settlements sweetbriar and “gorse for hedges,” two plants which “we could have well done without” By 1867, horticulturalists and gardeners had begun to contribute plants from their gardens to the “weed flora of New Zealand.” he said. Now there were well over .400 special of weeds which began in that manner. Some plants were deliberately removed from gardens to the countryside by gardeners while others had an “inherent ability to escape.” Examples of those which “escaped” of their own accord were the Michalmas daises which were to be found everywhere in Christchurch in cracks in the pavements and other berries and fruits which were distributed by birds.

“Horticulture,” said Mr Healey, “is like women’s fashions. Gardeners show enthusiasm for certain species at certain times new varieties are introduced and others are discarded. Those that are discarded find their way to the roadsides and the cliffs where now you can see horticultural varieties that were popular many years ago.” Gardener’s Responsibility

Some of these were harmless but those of a noxious character were the ones of concern. The most serious were the poisonous weeds such as Cape tulip, hemlock and oleander. These were of great danger to stock. Others such as water hyacinth blocked waterways while the blackbery, gorse, heath and some species of broom ruined large areas of good pasture land. “This position can be guarded against by gardeners.” said Mr Healey. There are a number of things which are responsiblities to gardeners in return for the pleasure they receive from their horticulture. When a plant appeared to be rampant it should be effectively killed, not merelv discarded; gardeners should be precise in the naming of plants or they could be trapped into a sense of false security about potential weeds.

Mr Healey particularly emphasised that horticulturalists should not succumb to the temptation of bringing new plants into the country in an illicit fashion. “That is how many of our weeds came here.” he said. “It could have been how nassella tussock was introduced to North Canterbury—it could have been brought here by one of those people who bring in seeds of plants they particularly like in their pockets. “Exercise care in disposing of plants from your gardens,” said Mr Healey, “or you could well add to the weed flora of New Zealand and to the amount of money that is collected each year for its eradication.”