The Prince and Princess of Wales made their first Royal Garden Party appearance of the year on 20th May at Buckingham Palace on behalf of the King. They struck lucky with the weather and Kate looked stunning in a butter yellow dress and her wedding earrings as they chatted to guests.

Her outfit caught my attention first, but later that I noticed a sweet detail on Prince William’s suit. Blink and you’d easily miss it, but the future King also had a flash of yellow with a tiny flower in his buttonhole.

King Charles often wears cornflowers, including in a 2013 portrait, with Tatler claiming that the endangered bloom symbolises his passion for conservation. I don’t know whether there’s another symbolic meaning behind Prince William’s choice of flower, but it spoke volumes to me because it tied in with Kate’s outfit.

Although his boutonniere (as it’s often known) was a brighter shade than his wife’s pastel Emilia Wickstead frock, it was the only yellow detail in his look. To me, this suggests that it was a carefully thought-out choice as he didn’t just choose a blue or red flower to match his shirt or tie.

Another thing that has me convinced this was a deliberate choice on Prince William’s part to coordinate with Kate is that I’ve seen this before. Last year the Princess didn’t attend any of the Royal Garden Parties as she was undertaking cancer treatment, but in 2023 she joined one in a bluebell-toned Elie Saab dress.

It had sheer sleeves and a feminine bow at the neckline. The Prince of Wales wore a very similar outfit as he did this time around, but in his button hole he had what looked to be a small bunch of blue forget-me-nots.

These pretty flowers were Princess Diana’s favourites and featured in Meghan, Duchess of Sussex’s wedding bouquet for this reason. As well as being a potential nod to his late mother, the shade of blue almost perfectly matched Kate’s outfit.

The future King also matched the future Queen’s blossom-pink dress at a 2019 garden party with his boutonniere. He doesn’t do it every time they go to a Royal Garden Party together and on certain occasions, I suspect this could be because of the tone Kate went for.

In 2022, for example, she stepped out in a mint green frock that would’ve been incredibly difficult to match to a flower that hadn’t been artificially dyed. On other occasions, he’s worn a simple white handkerchief in his breast pocket instead.

Whatever the reasons, I think it’s very heart-warming that Prince William matched with the Princess of Wales’s dress again this year. It could be seen to highlight the unity between them as a couple and I’ll be keeping an eye out at the next formal event to see if it’s done again.

There’s one more Garden Party to come this year and it will be held at the Palace of Holyroodhouse in Edinburgh on 1st July. The Waleses might not attend this, but they shared a message on social media after the recent one expressing how “lovely” it was to meet “so many inspiring guests” from all over the UK.