Botanic gardens around the world are running a competition for 11-19 year olds to design a 2012 Olympic garland that only contains native species.Organisers hope it will help raise awareness among young people about the threats facing biodiversity.Winning entries will be on display in London next year while the city plays host to the 2012 Games.The Plant Champions competition was launched by Tanni Grey-Thompson, Britain\'s most successful paralympian.It is being organised by the UK-based Botanic Gardens Conservation International (BGCI) in partnership with US-based Fairchild Challenge, which runs an annual environmental awareness event.BGCI director of education Julia Willison said that because London was going to host the 2012 Games, it was decided to develop a global competition with an Olympic theme.\"The philosophy behind all of these challenges is to raise awareness about the environment, but because our organisation is a plant conservation body we try to find some link to plants,\" she told BBC News.\"Because it is going to be the Olympics, we thought that we could get children to design wreaths.\"The BGCI says plants and the Olympics have an association stretching back more than 2,700 years to the time of the ancient Games in Greece, with winning athletes being crowned with olive branches.\"The olive tree (Olea europaea) was considered sacred and symbolised peace and victory,\" it stated.\"Native to the Mediterranean Basin, the olive was important for nutrition and health, and was valued economically.\"We want students to update the idea of a traditional wreath, and create one that is fit for an athlete competing in London 2012.\"So far, 15 botanic gardens around the globe - including ones in Australia, Canada and the US - have signed up to competition.\"It is not a huge number at this stage,\" Ms Willison admitted, \"but these gardens can reach out to many, many schools and we are still in the process of promoting it.\"She hopes that the link to the largest sporting event on Earth will encourage children to learn more about the planet\'s plant diversity.\"By doing this project, the idea is that they will be taught, through their schools, what their native species are.\"The teachers themselves will get to understand about the different types of plants and this information will get passed on to the children.\"In order to enter, children will have to complete a number of tasks, including making a list of the plants (including scientific names) used in their wreaths, explaining why they chose those plants, and taking a photo of the finished garland.Entries will be have to be submitted to one of the botanic gardens involved in the project, where the best entries will be selected and sent to the BGCI for a final round of judging before the overall winners are selected.Lord Coe, chairman of the committee organising the 2012 Games, said: \"Plant Champions is encouraging children worldwide to fulfil their potential.\"I am proud that with the help of partners such as BGCI, we are delivering our vision to use the power of the Olympic Games and Paralympic Games to boost participation in fantastic education projects like Plant Champions.\"The competion closes at the beginning of April, with the overall winners being announced in May.