I'd like to collect some common vetch seeds from roadside patches
to see if they're useful as groundcover. In this (very dry) year
the bloom is good, which augurs well for drought tolerance.

Collecting fully-ripe seeds is difficult. The county mows road
shoulders at irregular intervals, making the plants hard to find
at all and scattering what seeds might be present.

I've tried grabbing a few whole plants at random times, hoping to
find a few mature pods, but it seems that if visible flowers are
present essentially no pods are filled out. Once bloom ceases the
plants are surprisingly hard to find among the other weeds.

Is there any technique to help unripe pods mature enough to yield
viable seeds, either left attached to the plant stem or taken
off? Might putting the cut stems, with pods, in water like cut
flowers allow any useful development?

Thanks for reading,

bob prohaska