Maris Wigeon

Emily Hurst, a milliner who specializes in crafting and designing high-end straw hats for women, said it felt surreal to learn of the king's unexpected offer after she told him about her problems sourcing the straw she needed.

Milliners such as Ms. Hurst are struggling to get hold of Maris Widgeon, a traditional British heritage wheat variety, as poor harvests and changing weather patterns have led to unpredictable supplies.

But now Ms. Hurst has been given a field full of the wheat at the Sandringham Estate in Norfolk, the private country retreat of the king and queen.

Speaking on BBC Radio 4, Ms. Hurst said, quote, we've got a whole field's worth here.