According to An Economic History of the English Garden, between 1820 and the present day, 15,652 gardening books have been published in the UK alone. That’s not the most astonishing number in this book, but it does make you wonder whether there is really room for another one. Roderick Floud thinks so, and succeeds in proving his point, largely by contemplating the horticultural phenomenon coldly and unsentimentally in terms of one thing: money.

And what a lot of money! Beginning with the great gardens of the 18th century, which were formed by the aristocracy and other grandees (including, of course, royals able to beautify their acreage with the aid of public funds), right up to the garden centres and allotments of today, the English have spent, by Floud’s calculations, almost unbelievable amounts. Here are a few examples (all figures reflect today’s values): between 1760 and 1800, the Crown laid out between £800 million and £1 billion on parks and gardens; the lake and dam at Blenheim took six years to build and two more to fill, and cost the fourth Duke of Marlborough £35 million; the sixth Duke of Devonshire paid £25.6 million for the Great Stove, a huge conservatory designed by Joseph Paxton, at Chatsworth; in the 1770s, the designer Lancelot ‘Capability’ Brown earned £20 million working for the banker Robert Drummond at Cadland, where he created what is described as one of his ‘smallest gardens’; it is estimated that in 1868 it cost £569 to produce one pineapple; an Atco lawnmower would set you back £10,500 in 1921.

If these numbers appear out of line, we must recognise that to arrive at them Floud has chosen a slightly unorthodox method. Instead of simply multiplying the actual figure expended in, say, 1700 by the change in the value of a pound since then, he compares the change