National Register of Historic Parks and Gardens

In England, the Register of Historic Parks and Gardens of special historic interest in England provides a listing and classification system for historic parks and gardens similar to that used for listed buildings. The register is managed by English Heritage under the provisions of the National Heritage Act 1983. Over 1,600 sites are listed, ranging from the grounds of large stately homes to small domestic gardens, as well other designed landscapes such as town squares, public parks and cemeteries.

More information on the Wikipedia page

The website is.