Pink-Eye Purple Hulls, as well as other types of peas are--semi-vineing---not to the point of "sticking" or "trellising" as you would a Kentucky Wonder Pole Beans, but just a little. The newer strains of Pink-eyes are even less so. Yields, like most things, can be affected by soil conditions, and rain fall etc.
Havesting normally occurs when the pea is "filled out" regardless of the color of the hull. Obviously the Purple Hulls will begin to exibit shades of purple on the hull. The pea itself will be green with an oviouos pinkish eye---not black. As the peas mature on the vine the hull darkens, and the pea goes from a green color to a cream color. The freshest, and best tasting are when the peas are green. As they mature, they're still good--just not as good. Of course if allowed to completely dry---they could treated/cooked/eaten as any dry bean or pea.
Suggest you shell and eat ASAP for freshest taste.
Yield on these 8 125' rows was about 1.5 bushels per row--A little disappointing--but not bad.
None of these are ready for harvest....