Can't change the colour of Tk button text

[Larz60+]

with ttk you can use a style command, can't remember if this works with plain tkinter, you'll have to check.
But, with plain tkinter you can change background and foreground colors to get same effect, example:

>>> import tkinter
>>> root = tkinter.Tk()
>>> xx = tkinter.Button(root, text='Hello', bg="white", fg="blue")
>>> xx.pack()
>>> root.mainloop()