Work to remove selected vegetation from the walls of Knaresborough Castle is now underway as part of efforts to protect and preserve the historic landmark.
The work, which is expected to be completed during July, follows advice from Historic England and local experts.
The conservation programme will begin on the castle's outer walls before moving onto the Keep.
Plants with woody stems will be cut at the base and treated with herbicide, while non-woody plants will be left in place as they do not pose a risk to the scheduled ancient monument and continue to provide aesthetic value.
Roots will be allowed to die back naturally to avoid damaging the castle's historic mortar, while extra care is being taken to protect Maidenhair Spleenwort - a rare fern found in only a handful of locations across the UK - along with other important plant species.
A spokesperson for Knaresborough Castle said:
"Our priority is to protect and preserve the castle for the future. Thank you for your understanding."
Despite the work taking place, the castle and its Keep will remain open to visitors as normal throughout the project.

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