Debbi, I generally find that if I can crush the seed head between my fingers, the seeds are ready to harvest. If the seed heads are too hard to do this, wait and try again later.

Thank you! So far the seed heads are hard but not brittle or dry enough to crush. I did pick one apart and there were a few black seeds. I'll wait a little longer, but does it usually take a few months? Thanks!

Hi, yes I wait for quite awhile after the seed heads form. I haven't really counted the months but it takes some time.
I'll include a link below - I love penstemons.

Here is a link that might be useful: NIce penstemon link

Thanks! I'll just have to be a little more patient then. Thanks for the link. I love the color of strictus (sp). It just doesn't do well for me. The husker red does really well here and I am anxious to grow some from my own seeds.

I have the same question, but my flowers are white. For seed trading, is it preferable to just get whole brown seed heads from someone, since the seed is so small, or should I wait until they all crack to harvest it? Some pods are ready, others not. Put it all in a paper bag and wait, or?...