Beth Chatto's Gravel Garden. Allium Nigrum and a very wide selection of allium bulbs in the UK, try Bloms. Cool colors in a hot garden: allium Nigrum is planted with veronica 'Kapitan', stachys byzantia, and a cristophii.
Blue Mountains Botanic Garden, Mount Tomah is located in the World Heritage listed Greater Blue Mountains on the summit of a basalt-capped peak, 1,000 metres above sea level. The 252 acre garden has a large collection of plants from around the world, particularly the southern hemisphere, and is the ‘cool climate garden’ of the Royal Botanic Gardens Trust.