There's an incredible amount of L. bicolor growing near swim's house, and swim wants to attempt an extraction. What would increase yield- what time of year is best, and does the location of the plant (sun or shade) matter?

I've been told fall collected foliage gives higher, more consistent yield.

Make sure you have a correct ID on it many legumes contain toxic alkaloids.

TLC plate comparing Lespedeza bicolor to ACRB.
Result: Even being much more concentrated than the ACRB sample, the L. bicolor did not visualize any spots.
Note: Although the crude samples veered horizontally on the plate, the result is still fairly clear.
Additional images identify this specific plant tested. (foliage, stem bark, root bark)

Thank you for your work.

About the identity of your plant. I guess is not a Lespedeza Bicolor, usually Bicolor has very round and oval leaves in the base of the shrub. Also I cannot see the change of color on the back of the leave.

My guess is that is that your plant is a Lespedeza Nipponica (or Lespedeza thunbergii Nakai subsp, which has a lot of subspecies).

Even so, it would be great if you can make a test on just the seeds and the seed pods (in Autumn). Since, amateur bio-essays (by smoking) and other analysis have shown the presence of 5MeO-DMT in the seeed of Lesp. Bicolor. It is highly probable that the seeds of your plant could also have the same compound.