British Ecological Society Press Release
Friday 17 May 2013
Have aliens landed in your garden?
Plants that could land you in court if they escape from your garden, hybrids notorious for sparking disputes between neighbours, and species we didn’t know existed 100 years ago all form part of the British Ecological Society (BES) exhibit at this year’s RHS Chelsea Flower Show.
Both the RHS Chelsea Flower Show and the BES celebrate their centenaries in 2013, and to mark the occasion the BES is bringing a garden to Chelsea for the first time in its history. Split into two micro gardens with radically different planting, the BES exhibit illustrates how changing fashions and ecological knowledge have influenced British gardens over the past 100 years, and the impact of these changes on British biodiversity.
The BES was founded in 1913 by Sir Arthur Tansley, who would find familiar the planting in the 1913 half of the BES garden, which includes species such as Japanese knotweed, ferns and monkey puzzle. He would, however, have been unfamiliar with some of the plants in the 2013 garden, including dawn redwood, Leylandii (Cupressus × leylandii) and restios.
The gardens are designed by ecologist and garden expert Dr Ken Thompson, who explains: “Some of the 1913 plants, like ferns, are less widely planted now because they have simply become less fashionable or, like the monkey puzzle, people have finally realised just how big they grow, and that sticking them in suburban front lawns was never a very good idea. Others, like Japanese knotweed, have fallen from favour for reasons that are all too obvious. Japanese knotweed, of course, is a nightmare if it escapes into the wild.”
The cost of Japanese knotweed to the British economy is estimated at £166 million per year, mostly accounted for by the costs of control and removal. While it is not illegal to grow Japanese knotweed on your own land, it is a criminal offence to cause or allow it to escape into the wild.
Leylandii, the hybrid conifer Leyland cypress, first arose in 1888 but was not commercially available until the 1920s, and only became popular from the 1950s. “If you don’t like Leyland cypress, and most of us don’t, the good news is that it can’t escape into the wild because, like many hybrids, it’s sterile,” he explains.
Other plants in the 2013 garden were unknown to the gardener of 1913. Dawn redwood (Metasequoia glyptostroboides), a beautiful deciduous conifer, was first discovered in China in 1944, and is now widely grown in gardens. Like ginkgo, it is a ‘living fossil’, known from the fossil record before it was discovered as a living plant.
Another 2013 plant, or group of plants, is the restios, slightly odd southern hemisphere relatives of the grasses. According to Dr Thompson: “The fashion for restios is recent, but so is the ability to grow them from seed. Only in 1995 was it shown that the seeds of most species will not germinate unless exposed to smoke. The active chemical in smoke was revealed by Australian researchers in 2004 and is now known, for short, as karrikinolide, after an Aboriginal word for smoke.”