The tree was officially planted by society member Mel Hogue and blessed by the upoko (chief) of Ngati Huirapa runanga ki Puketeraki, David Ellison, on behalf of the mana whenua of Otago.
He performed a karakia to commemorate the gold anniversary of the society and blessed the tree with holy water.
''People will walk past this spot and pay their respects for those who have passed and those who are living,'' Mr Ellison said.
Society president Alan Shanks welcomed a group of about 25 to the small area reserved for their tree in the gardens.
''[The tree] is something that people can come and see in the future and be reminded of what we do and what we've done in the past,'' he said.
Many in the crowd had been helped in the past by the society, which was started in 1965 and provided support and care to those with multiple sclerosis.
''Let's hope that in another 50 years, the organisation will still be here to help with the community,'' he said.
Society manager Tania McGregor said it provided help to people with multiple sclerosis all over the Otago region.
by Samuel White
