The Birr Castle Box Hedges

Birr Castle says these are the tallest box hedges in the world, and Wikipedia says Guinness agrees. What nobody agrees on is how tall that is. The castle itself gives no figure. Travel writers have filled the gap freely. One guide says 12 metres, another about 40 feet, the Irish Times 31 feet, another 32. That puts them somewhere between nine and twelve metres, which for a plant most people know as a knee-high border is absurd enough without settling the decimal. The age is just as loose. One guide says they were planted in the 1780s. Wikipedia says more than 300 years. The national heritage tree register, which lists an avenue of multi-stemmed box at Birr, gave 200 to 300 years in 2009. So these hedges are at least two centuries old, perhaps more, and any single date you read is one source's guess. What they are is easier to say. Two walls of clipped box face each other on the lower terrace of the Formal Gardens and make a green corridor several times your own height. Box is a slow grower, so the height alone tells you how long these walls have been kept. The Formal Gardens are inside the ticketed demesne, open all year. The castle is a private home and not part of the visit.