Pretty but Invasive: Stopping the Spread of Monkey Flower

Aaron Millar, a master’s student at UC, is researching ways to stop the spread of monkey flower, an eye-catching North American plant that is invading pristine areas of Canterbury and Otago.

Colloquially known as the monkeyflower, the plant is particularly prominent in Canterbury and Otago, although found throughout the country.

“It likes a lot of light, so it’s commonly found in farm culverts, roadside ditches and small streams. If you’re driving in the summer and you see a ditch full of yellow flowers, you’re probably seeing some.

“The big concern though is that it’s gotten a foothold in some of the culverts and creeks in some really pristine places like Lewis Pass, and the areas around Mount Cook and Lake Tekapo,” says Millar, who specializes in evolution of invasive species. weeds.

“What is worrying is that it is found in increasingly remote mountainous regions.”

Millar says the monkey flower grows extremely thick and can completely fill small streams.

“It has all sorts of problems for water flow. The landowners have to dig it up if it gets too bad, and I’ve spoken to the respective Council staff who also have to try and manage it from their end, so it’s is a big headache. And you don’t want something that can grow so quickly to become established in natural waterways, because that can drown out the plants that we want.

For her MSc in Biology, Millar is researching why the monkey flower does so well in such a range of environments.

“Unfortunately it’s one of those stubborn weeds that you can never get rid of completely, and I’m sure any gardener can relate. But we know they hate shade, so by planting things like clumps or small trees over streams it can be shaded in. This reduces its density by up to 80% which is enough to keep it from clogging streams or cause major problems,” he says.

Millar’s interest in Monkey Flower was piqued in 2017 when he helped another UC student on a summer research fellowship. They found a lot of variability between different plants in different parts of the country, and Millar wanted to see if these differences could be linked to locally important factors. He recently received $9,130 ​​from the Brian Mason Scientific & Technical Trust to help fund his work.

Monkeyflower, more formally known as Erythranthe guttata, was introduced to New Zealand by Pakeha settlers during colonial times.

Native to North America, it was kept as a garden plant in Britain, and they liked the look of it enough to bring it here. Scotland is also struggling with its invasive impact.

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