The RHS first became involved with the Chelsea Hospital in 1905. Three years before, it had leased the grounds of Holland House in Kensington to hold what was first advertised as a Coronation Rose Show, but which turned into a more general show (with not many roses) by the time it actually opened in June. Two further two-day summer shows took place at Holland House in 1903 and 1904, but then, to the general satisfaction of exhibitors and press, a three-day Summer Show was staged in the Hospital grounds, a more spacious site than Holland House had allowed, with room for five tents. The Summer Shows reverted to Holland House for the years thereafter, except in 1911, when both it and Chelsea proved unavailable, and the Show was held at the Olympia exhibition hall.
The Royal International Horticultural Exhibition of 1912 demonstrated, at a time when the complaints from the Temple were increasing annually, what an excellent site for a show the grounds of the Chelsea Hospital provided. Accordingly, for 1913, the Great Spring Show was moved there, while the Summer Show reverted to Holland House. Despite the First World War, the show was held 1914 - 1916, but was cancelled in 1917 and 1918.
By the roaring 1920s, the Chelsea Flower Show was back in full swing, the famous Chelsea tea parties were established and Royal visits resumed. In 1926 the show was held a week late due to the General Strike. In 1937, King George VI and Queen Elizabeth celebrated their Coronation Year, and to mark the occasion, a superb Empire Exhibition was staged. It featured wattles from Australia, pines from Canada, brilliant gladioli from East Africa and even a big prickly pear from Palestine.
The show was cancelled during the Second World War, as the land was required by the War Office for an anti-aircraft site. Some doubt arose as to whether the show would resume in 1947. The majority of exhibitors wanted a postponement, as stocks of plants were low, staff much depleted and fuel for greenhouses was obtainable only with special permits, but Lord Aberconway (then RHS President) and the RHS Council felt strongly that the show should resume as soon as possible. As it turned out, the show went ahead in 1947 and it was a great success.
To get there from the Americana; take the Jubilee Line southbound from Baker Street to Westminster. Change there to the District Line westbound and take the first train to Sloane Square. It is just a short walk to get to the show and the route is signposted.