X - 'xcellent

 

 After that lengthy W, you may be happy to see X has only one entry!  

Xerochrysum, Everlasting, or Strawflower 

Mine are quite small as xerochrysum go, they can be much larger and in brighter colors.  These grew from 25 cent Dollar Tree seeds, wintersown last year.   They do last, I have them still in my hutch.