On an unremarkable hill outside Fyshwick is one of only four sites in the world where the Ginninderra peppercress exists.
It's not the prettiest plant, but it was assumed to be extinct up until 1989, when a small batch was found in Belconnen.
Since then, three more sites have been found, with ecologist Alison Rowell discovering the most recent one near Symonston in January.
Ms Rowell said the herb's reduced population was a sign of the human hand's effect on Canberra's native landscape, and as we changed the environment more and more, we risked losing all our native flora and fauna.
"It's like Jenga," Ms Rowell said.
"How many can you pull out before the whole thing collapses?"
Ironically, the fourth site near Symonston was discovered when Ms Rowell was mapping the habitat of another critically endangered species native to the Canberra region, the golden sun moth.
"I was very excited," Ms Rowell said.
It was while doing that mapping that Ms Rowell stumbled upon the tiny herbs of peppercress, scatter-shot in the dirt and each less than eight centimetres tall.
She said it was lucky the plant was found in land marked for conservation, and now researchers could work to discover more about the plant.
ACT Parks ecologist Brett Howland visited the third peppercress site, which was discovered near Jerrabomberra in February last year, with Ms Rowell on Wednesday.
The former paddock is home to some 300 species of plant, though only half of them are native species.
But in some small spots the peppercress, which resembles a rougher thyme, has managed to survive.
"It's one of those classic cases for endangered species; where we find them now is not where they used to be," he said.
Dr Howland said the small piece of land behind the Alexander Maconochie Centre is one of the largest connected grasslands in south-east Australia.
It is home to plants like the blue devil, the button wrinklewort and a plant related to the ACT emblem, the royal bluebell, as well as animals like the rare striped legless lizard and the endangered earless dragon.
The peppercress would have favoured flood plains and riverbanks, but it had seen habitat loss from exotic grasses and agriculture.
Dr Howland said a renewed sense of the importance of managing Canberra's natural environments had been sparked by Ms Rowell's fluke discovery.
"We've been walking this land for ten years and could never find it," he said.