Parts of Europe’s longest and oldest green wall will receive a “severe pruning” ahead of restoration works on Madeira Terrace.
The pruning is being done after a recent survey revealed the wall behind the terrace needs to be strengthened.
Brighton and Hove City Council said the Japanese Spindle plants will be protected where possible during construction.
Workers will be preparing Madeira Terrace this year ahead of restoration work set to take place in Autumn next year.
A council spokesman said: “The Euonymus spindles will be protected where possible during the construction phase and other plants will be taken away and colonised to allow replanting later.
“Cassettes with special bio-diverse planting mix inside will then be installed against the wall. This will support development of a new ecosystem below the Terrace without long-term detrimental impacts on the rear wall.
“Contractors will begin cleaning up the site this year and undertaking preparation for restoration work starting on site in autumn 2023. This will include some severe pruning of the spindle to protect it while work takes place around it.”
“A recent survey showed that the wall behind the terrace needs to be strengthened to continue to do its job of protecting the cliff behind from erosion. Our challenge is to stabilise and support the wall and Terrace while protecting the Green Wall wherever we can and replanting in a manner that is sustainable.
“The remaining spaces between the spindle plants will be home to a whole new ecosystem with both original and new plants. It will be thriving with invertebrates and do the same job of cooling and ventilating the space as the current wall does.”
It said that only “minimal cutting” should have occurred.
The council was also reported to Sussex Police for an alleged wildlife crime after the cutting.
The council said the section of green wall has experienced significant regrowth thanks to volunteers and council officers.
Planning permission was granted on November 2 for restoration of Madeira Terrace.
This will see 40 of the 151 Grade II* listed arches restored.