New Zealand's clean and green image has come under attack from a visiting UK businessman.
Our use of weed sprays across streams and pockets of native bush was "Neanderthal", said Graham Gibbons.
He and his wife Ruth Larsen have visited her family in Whanganui during most of the last 15 years. They love the Parapara stretch of SH4, but were devastated to see large areas of hilly farmland near Raetihi sprayed off this year.
Mr Gibbons owns a landscaping business in the United Kingdom. He has 13 staff who work mainly on big private estates, including for members of the royal family.
He uses the herbicide glyphosate himself, but only on private property, with approval, and only in small amounts on especially difficult weeds.
"We don't spray it around the base of trees or anywhere near waterways."
Glyphosate is extremely damaging to certain life forms in water courses, he said, and even the version made for use in water is being subjected to tests.
There has been a lot of debate about the herbicide in Europe. The UK has decided it can be used there for another five years, but it has been banned in some countries and has been found in bread and other foods.
Mr Gibbons was shocked to see that pockets of native bush had been sprayed in New Zealand, "the most deforested country in the world".
He said 20m margins should have been left along waterways - and even if they had been, some glyphosate would have reached waterways through spray drift.
"I was actually quite devastated to see it. It would never happen in the UK. We have very strict laws about it. Other people that I have spoken to think it's a bit Neanderthal."
He's also noticed how much spraying is done on roadsides.
"You can have a stop sign two metres high, with spray around the bottom two metres square. The grass is never going to get that high."
In the UK, vegetation is cleared away from road markers twice a year, by council staff with weedeaters. Using spray is quicker and cheaper, Mr Gibbons said, but it will get into waterways.
"It's damaging your country."
Seeing spray use so widespread makes him worry about drinking New Zealand wine. In France and Italy herbicides aren't used in vineyards, he said.
His wife said organic food was in demand in the UK but she hasn't seen much in New Zealand.
"Where's your organic stuff? We are so much greener over there."