Reference

The thistle has been a symbol of Scotland for centuries, but there is no specific individual credited with designing the first version of the famous 'Thistle' symbol. The thistle first appeared as a royal symbol on silver coins issued by James III in 1470, marking its use as a national emblem of Scotland. The exact origins of its adoption as a symbol are not clearly documented, and it is more of a traditional emblem rather than a designed logo by a specific person.

For more information, you can visit Historic UK.

Here is an image of the thistle, which is widely recognized as a symbol of Scotland: