To commemorate the Queen’s Platinum Jubilee, the Tower of London will be transformed with 20 million flowers.

Her Majesty, 95, will be the first British Monarch to be honored with a Platinum Jubilee, signifying 70 years of service to the people of the United Kingdom, the Realms, and the Commonwealth.
Historic Royal Palaces has revealed their incredible idea to demonstrate their admiration for the Queen.
They will add color to the moat with flowers that will linger from late spring to late summer, fade in autumn, then return in spring the following year.
In a project named Superbloom, urban horticulture specialists at Sheffield University have cherry chosen 29 different species in a range of colors to come alive at different periods of the season.

20 million flowers for Queen's Platinum Jubilee - London Airport Transfers — 20 million flowers for Queen’s Platinum Jubilee – London Airport Transfers

The flowers have been planned to blossom in whites and pinks in June, just in time for the Queen’s Platinum Jubilee celebrations. In July, there will be a flood of blue and purple blooms. In August, gold, yellow, and orange will take over the vast expanse.
The last time flowers were planted in the Tower of London, they attracted a lot of attention.
888,246 ceramic poppies were put at the time to commemorate the centennial of World War I’s start in 2014.