"They are both a huge public nuisance," Dan Gerard says.
Hemlock, he points out, can be very poisonous to touch for humans and most animals, and deadly to eat.
And barley grass, he says, has extra-sharp tips that can get into animals’ coats, ears and paws and only travel in.
Local vets regularly see pets that have been in contact with barley grass at certain times of the year.
Robert Win, Otago Regional Council’s (ORC) team leader biosecurity and environmental implementation, says barley grass and hemlock aren’t currently listed as pest plants in its pest management plan.
However, he notes "hemlock is a noxious plant that is poisonous to livestock and humans".
And barley grass, he adds, is "an agricultural pest that can impact livestock health and pasture quality".
A Queenstown council spokesperson says its parks team has a regular mowing and maintenance schedule for council-managed recreation reserves, tracks and road reserves/verges.
"Part of this involves pest plant work in certain locations which is guided by ORC’s regional pest management plan.
"Our work programme is based on experience, but there will always be occasions when particular areas become overgrown in advance of scheduled work, especially after spring rainfall — recent months have been wetter than most.
"Hence we welcome feedback and updates from residents and the wider community.
"The best way to notify us is via our ‘snap send solve’ mobile app or emailing our customer services team via services@qldc.govt.nz."
