Gardening in adversity is my theme of the moment. It stops us all complaining about our local problems. What is a hot summer in England to gardeners who have had to cope with years of drought in Australia? What is a single badger to people in America who are invaded by urban deer? I have been widening my grasp of global garden problems by research in that land of plenty, Texas.

One plant from the home of oil rigs and wildcat drillers will be familiar to British readers: the famous yellow rose. During the wars with Mexico in the 1830s, the Texan generals profited from their secret weapon across the Mexican lines. She was Emily, a young lady of mixed-race origin, a “yellow” in Texan language of the time. Taken captive, she had one of the least challenging missions in military history, to seduce a senior Mexican after lunch. She bagged the top general and sent a message to the Texans, who promptly attacked his leaderless troops. The yellow rose became a Texan icon.