Monty Don has opened up about King Charles' green-fingered secrets and revealed that he's "genuinely serious" when it comes to gardening.

In a recent interview, the BBC Gardeners' World star explained that both the King and Queen have a "real personal interest" in gardening and dubbed the King "keen and good".

He also revealed that King Charles, 76, who is widely-known as a passionate gardener, particularly enjoys heading out into the arboretum and even prunes his own trees.

Speaking to the Radio Times, Monty said: "Certainly, the King is a genuinely serious, keen and good gardener. I also know the Queen loves gardening. She's been to my garden. Both of them have a real personal interest.

"I know the King enjoys working in the arboretum on the Birkhall estate and prunes the trees himself."

The much-loved horticulturalist went on to share what it was like to visit Charles' estate in Scotland, humbly saying that he feels "privileged" to see anyone's garden and said it was, in "some ways", the same with Birkhall.

However, he conceded that this statement could be "slightly disingenuous" as he understands that not many others would be afforded the opportunity to visit, reports the Telegraph.

Earlier this year, he told the publication that the "incredibly impressive" King "does his homework thoroughly", adding that both Charles and the Queen are "excellent".

Charles has enjoyed gardening since he was child, having previously planted vegetables with his sister, Princess Anne. In fact, he loves it so much that he said in 2018 that "all I really long for is to plant trees" as he gets older.