Natural. As the vines get older, the temps climb, P. sativum tends to dry from the bottom up at the end of harvest..

So do I need to start picking all my peas now? Will there be further maturity?

I assume there won't be any new growth, correct?

Just pick them as they are ready for use. The last few will be at the tips of the vine. the numbers will get smaller and smaller. When they become too sparse to be worthwhile, pull the vines and plant a summer veggie.

I just yanked out my Super Sugar Snaps last weekend, and planted a late corn crop there.

Just one small point. Rather than pull the plants, cut them down. That leaves the roots with their nitrogen containing nodules to decompose in the ground and contribute a little to your next crop.