Back in World War I and World War II much of the fighting was in the trenches.
The men lived in those trenches – they ate there, slept there, died there which meant disease was rife, says Rongoā Māori practitioner Donna Kerridge.
"So the Māori Women's Welfare League ofthe time went out and harvested the koromiko tips and they dried them and sent them to our troops at the front line who shared them with our allies to keep our people more safe in the trenches."
Koromiko is known in herbal medicine as something that can be used to help not only dysentery, but also constipation.
She says unlike other forms of healthcare, it wasn't focused on disease.
"Rongoā's more about people than it is about disease. It is lifting that vitality in people."
The practice also uses medicines from the land and the sea to help people deal with short term issues like aches and pains, coughs and colds.
Part of that was learning how the environment was connected, Kerridge says.
"It's as much about helping people feel their connection to the land in order that they can learn from the blueprint that nature sets for us in terms of healing.
"When we look at a healthy, thriving landscape, there's a blueprint for what makes it healthy and thriving. When we pick up that blueprint and we overlay it for our human community and use the same philosophy, then we're in a much better place."
She says understanding the connections and how those connections work in nature is the key to learning to manage our own wellbeing.
"Flax is symbolic to Māori of how we live as whanau."
There is the centre shoot, also known as the baby, which is enveloped by the mother and father, and on the outside are the grandparents.
"No matter what you may be doing, you always protect that centre frond and the parents. Because without two people to raise that child, it can't grow tall and straight.
"We learn from the reflections that we see in nature about how to live our lives in a way that bears the best fruits for everybody."
Another example Kerridge uses is the mamaku, also known as the black tree fern.
She says its job is to heal Papatuanuku (Mother Earth) when she's been ripped apart.
"So if you look on a hilly landscape and you see mamaku ferns growing down the side, you know that land is prone to slipping."
Mamaku is also used to help women heal after childbirth.
"When you understand the gifts that plants, and other things bring to the land or to the ocean, then you know how to use them. But you know that not because I told you but because you understand the way the landscape hangs together.
"That knowledge is there, it's inherent. We have a whole lot of seen and unseen knowledge and when you can connect to the whenua you can make the best advantage of those spiritual ways of knowing."
Kerridge says teaching Rongoā Māori in a classroom was hard because it disconnected people from the land from which the knowledge grew.
"When I was learning a long time ago, I sat down and went through every book on the table that had anything remotely to do with Rongoā."
She says she was asked what she was doing by a teacher, she told him she had been studying all night.
"He said, 'why would you study there when you look outside the window and there's the environment that it's all about?'"
She says she now does her best all the time to teach in that environment rather than just have people hear her talking.
"The Māori way of teaching is through purakau, storytelling and so giving people real examples of how things work, allowing people to taste safely, to make things safely, to understand the stories or our ancestors about certain plants, about certain animals, helps us become part of that place and that's how we learn, and that's how we teach."