Feverfew Harvesting

I would like to know how fevefew is harvested. I know the active ingredient is in the leaves. Are the leaves picked off? Are all above ground material cut and baled? Are only the top 6 inches cut like St. John's Wort? Is there a machine available to harvest with or is it done by hand?
I am writing an article on fevefew for Farming magazine by the Western Producer.

According to a leading Canadian feverfew grower, the entire above-ground biomass is cut just as the plants are in bud and are beginning to flower. The material is cut with a combine and conveyed up into a wagon behind the combine. Cutting the whole plant down to within a few inches of the ground is important because the plants then "roll" up the conveyor easily.
The material is dried in a drier. Once dry, a stripper (a machine with belts running in opposite directions) is used to separate the leaves from the stems.