The latest theft involving a woman on an electric scooter with a wheelie bin at the front was caught on the security cameras at Mona Vale.
Head gardener and Botanic Gardens collections curator Ben Lay said it was one of a dozen thefts targeting the heritage gardens over the past six months.
"There is another couple with an alsatian, they're quite distinctive. They live quite close and they've been watching us for some time," Lay said.
Plants, including roses, ferns, and perennials, have been dug out overnight and up to 150 tulip stems have been cut each night.
They already have CCTV cameras and a neighbourhood watch programme to keep an eye on the garden.
"We've got things in place and we're just reviewing what we can do."
Unfortunately, those regular attacks will now have an impact on what the public gets to enjoy.
Lay said the gardeners have decided not to replant some of the stolen species because of the repeated thefts.
"I've just decided I'm no longer going to carry on with them because you know it costs quite a lot of money and a lot of our time and it's not worth the energy."
He hopes the culprits will find a conscience and leave the gardens to grow for residents to enjoy.
- By Emily O'Hagan, made with the support of NZ On Air
