The RHS Tree of Knowledge is a 5m tall woven willow tree created by willow artist Tom Hare to mark the 2010 United Nations' International Year of Biodiversity.
Actors Jeremy Irons, Greg Wise and Julian Fellowes were first to support the initiative and TV presenter Nicki Chapman has created a list of tips for people with limited spare time.
Ideas should be emailed to firstname.lastname@example.org and must be no longer than 50 words. Contributions can be viewed online at www.rhs.org.uk/biodiversity. The most inspiring idea for encouraging garden biodiversity will win two tickets to RHS Chelsea on Saturday 29 May and a special tour of the show.
Jeremy Irons advised: "Every time you see a plant or tree you haven't seen before, ask permission, take a cutting and put it in your garden and don't keep your garden too tidy."
Greg Wise wrote a poem to featureon the tree and explained his own garden supports biodiversity by including a pond, rotting pile of logs, a dead tree, a compost heap, leaf-mould bin, wormery, and water butt.
Nicki Chapman added: "It's so important we all try and make a difference."
Julian Fellowes explained: "An odd anomaly of the modern, fast-changing world, is that private gardens have become vital protection zones for a good deal of our natural wildlife."
The RHS Tree of Knowledge - in the Great Pavilion - complements the Continuous Learning RHS Biodiversity Display, which highlights the role gardens can play in slowing down the global decline of biodiversity. The RHS gardening advice team will also be nearby to help visitors with gardening, and especially wildlife gardening.
Guy Barter, head of RHS advisory, said: "The advice team find that gardeners are often surprised at how valuable their garden already is for wildlife and how easy it is to tweak their gardening to make it even more biodiverse without compromising their own enjoyment of the garden. Of course many gardeners have long been doing this, and our Tree of Knowledge seeks to gather all ways that Britain's creative and observant gardeners have found to make their gardens wildlife paradises."