Project convener Mr Les Box was ''totally disappointed'' to discover the theft early on Christmas morning.
He had gone to the dell to make preparations for the arrival that day of cruise ship visitors.
Helping convert a former quarry into a rhododendron dell had been the biggest project undertaken by the Lions club in its more than 40-year history, and each year club members spent hundreds of hours of volunteer work in the dell for the benefit of others.
Senior Sergeant Brian Benn, of Dunedin, said the theft was a ''despicable'' act.
Police were investigating and would like to hear from anyone who knew anything about the theft, or who had noticed suspicious activity in or near the dell shortly before Christmas.
The dell had been named in honour of the late Constance Lady Thorn, who, with her late husband, Sir John, the long-serving former Port Chalmers mayor, had worked tirelessly for the community.
In recent years, as part of the club's continuing planting programme, members had planted scented varieties of rhododendrons along the pathways - including the five fairly small plants stolen - to enable people who were visually impaired enjoy the facility even if they could not see the flowers.
Lions worldwide were recognised as ''Knights of the Blind'' and this was the club's way of providing an opportunity for people with sight problems.
Mr Box was upset ''some low-life'' had decided to deprive others of this pleasure, putting ''personal greed before community need''.
He said the dell was appreciated by many people, including Dunedin residents, cruise ship passengers, wedding couples and descendants of early settlers.
He urged whoever had taken the plants to return them.
