Instead of cutting the stalks of the pest plant and pasting them with herbicide, the contractors sprayed the whole wall.
There is one old man's beard still growing, Mr Ogle said, so they didn't even succeed in eradicating it. Now the couple are ready to give up.
"A neighbour told us we were wasting our time planting there, the council would just come and spray it. She was right," he said.
This latest setback follows a previous episode when, for years, they maintained the crib wall alongside the Portal Street walkway on Durie Hill, planting, weeding and trimming flowering plants.
They gave that up after a 2007 incident when Whanganui District Council contractors slashed through valerian flowers they had carefully deadheaded by hand.
The Ogles their efforts have been appreciated, council parks officer Lindsay Hyde told the Chronicle. He said he would give them some pelargonium cuttings to replace the sprayed plants, with replanting scheduled for early November.
Mr Ogle blames lack of communication from council staff and unsupervised council contractors for the problems.
Mr Hyde said contractors were responsible for supervising and training their staff and the council parks team was responsible for maintaining the crib wall.
Contractors provided a cost effective and timely service, and plants had to be trimmed to meet regulations, he said.
"This includes making sure sightlines and accessways are clear. On occasion, the trimming undertaken by the contractors is more than what Mr Ogle considers appropriate."
If council practices changed, Mr Ogle said local people could take on the maintenance of patches of council land - that would improve the look of some places, make people more attached to their surroundings, reduce vandalism and reduce council maintenance costs.
But Mr Hyde said there might be some fishhooks with that plan.
"We must ensure any work by individuals on beautifying an area can still be maintained by council contractors, and also that the volunteers are working safely."
