Final answer:
Green Park in London is known for only having grass and trees, and it contains the Canada Memorial. This is possibly due to an old royal edict. It is a distinctive feature among London's parks.
Step-by-step explanation:
The park in London, England, that contains the Canada Memorial and is known for having only grass and trees without any flowers is Green Park.
This characteristic is possibly due to an old royal edict that prohibits the planting of flowers. Green Park is one of the Royal Parks of London and is located near Buckingham Palace. Unlike other urban parks, which sometimes have strict rules regarding the use of grass and flowers, Green Park has maintained this unique tradition over the years.
It stands out among London's parks for its vast expanses of green space, which visitors can enjoy without the bright interruption of flower beds.