Queen Elizabeth II was dismayed by the flattening of her flowers in the garden at Buckingham Palace when President Trump arrived in 2019 aboard Marine One.

But his state visit there was a highlight of Trump's first term and valuable for Great Britain, building a relationship with the controversial U.S. president. Weeks later, the Queen tapped that relationship to smooth a diplomatic contretemps.

Here are five takeaways from USA TODAY's excerpt of a new book, "The Queen and Her Presidents: The Hidden Hand That Shaped History," by Susan Page. Published by Harper, it explores the Queen's relationship with a string of U.S. presidents, from the time she was a nervous young princess visiting President Harry Truman to the final state dinner of her seven-decade reign, in honor of Trump.

The president and first lady Melania Trump arrived at Buckingham Palace on June 3, 2019, aboard Marine One.

From the palace steps, Her Majesty watched with horror as the whirlwind of the helicopter's blades flattened her flowers and left divots on the lawn. "She was furious about that," a senior palace aide said.