Super Lawn Mowing and Gardening Services owner Scott Evangelou said his seasonal business was starting two months early this year.
"We are seeing the grass growing and some plants blooming. It’s unusual for this time of year."
Mr Evangelou was delighted with the unseasonably warm weather because it was providing unexpected cashflow.
Craig’s Can Do owner Craig Graham, of Dunedin, said he too had noticed an influx of customers calling in the past week, asking him to come and do their lawns and gardening.
"Some of the flowers that shouldn’t be flowering now, are popping up all over the place.
"I still mowed the odd lawn over the winter."
However, he said the growth spurt was not city-wide.
"It’s in different parts of the city. Some places you’ll go, it’s slow growing, and in other places it’s started growing way earlier than normal."
Dunedin Botanic Garden team leader and curator Alan Matchett said garden staff kept records of the flowering times of certain plants and found some of them were flowering very early, compared with previous years.
Camellias and bulbs, like daffodils and snowdrops, were flowering up to six weeks earlier than usual, but most plants were on normal trends, he said.
Dunedin City Council parks and cemetery manager Gareth Jones said staff also monitored grass-growing rates throughout the year, but had not noticed a dramatic increase in growth.
Mr Matchett said the city had many micro-climates, and because some parts of the city were warmer than others, plant life grew at different rates.
MetService meteorologist Tom Adams said the unseasonal growth was caused by a lack of very cold southerlies from the Antarctic ice shelf during the winter, and an increase in warmer winds from the north.
It meant July temperatures had been "well above average" across the South Island.
He said the first half of August was forecast to be "extremely mild" and temperatures would be "well above average" in the South Island, and the second half of the month was likely to be closer to average.
Southland and Otago regions were also expected to have "normal-to-below-normal" monthly rainfall.
However, he warned spring weather was often "unsettled and changeable", so potential for cold spells was still there.
"You can still have an above-average month, with some cold southerly blasts mixed in there as well."
