The world's tallest Box Hedges (so certified by the Guinness Book of World Records folks.) In The Red Tree Trail: 50 Trees of Distinction, Lord Rosse notes that "These hedges, traditionally planted when the Parsons family installed themselves at Birr in the early seventeenth century, have been attracting visitors and comment for over two hundred years. Boxwood is exceptionally hard and many of the clumps in these gardens were cut down to provide the propellers and other parts of the warplanes in the First World War. These particular hedges were luckily spared and are now just left to grow free above the point to which they can be easily clipped."