The property was bought by Mitchell and her husband, Ken, 25 years ago.
"We've just gradually grown."
But while it's hard work growing and maintaining such a big garden, Mitchell believes it's worth it.
"It's creative and it's good for the soul."
It's also very satisfying to have worked on a patch and then to see the result of all that hard work, she says.
She loves the fact that they have a lot of native wildlife, such as tui and bellbirds surrounding them.
"The bird life in the garden is amazing."
Some of the gardens in this year's ramble have been part of previous ones, but the rest are new.
Being over two days means more time can be spent exploring.
"It gives people a chance to view all the gardens at their leisure," Mitchell says.
The hope is that it will also draw people from outside the area.
"We're promoting Dannevirke as a lovely place to live."
The ramble starts at 10am each day and finishes at 4pm.
Entry will be $5 per person per garden.
Garden locations are as follows:
13 Carlson Street
34 Ruahine Street
Te Kiteroa Gardens – 221 Umutaoroa Road
Illsvilla – 8 Guinane Street
Glenheath – 185 Smith Road
71 Cadman Road
Brigadoon – 17 Empire Street
Kohatu Country Garden – 41 Maharahara Road
Reinline – 68 Ross Road