There's more. I heard from Lili Singer, horticulture journalist and expert. She once had a KCRW radio show I used to listen to regularly when I drove to work (nowadays I just walk to my office/dining room to work, and I only listen to the radio briefly during the commute. I leave dust-bunny sock-prints, not carbon prints). In any case, Lili Singer emailed me about lupines and the troubles I had with them in my own yard:

Regarding your un-success with lupine seed, don’t blame yourself – and please try again! Lupines can be tricky from seed but – as your photo shows – they’re well worth the effort and much appreciated by native butterflies whose larvae (caterpillars) depend on native lupines as a food source. To soften a lupine’s rock-hard seed coat, a boiling water bath and day-long soak are recommended before sowing. Even with this treatment, germination may be spotty and seedlings are vulnerable to snails and birds. Good drainage is key, and uneven watering (too wet or too dry) can be deadly.

All the more reason to make an exception and not kill the flowering plants on the Glendale Blvd. bridge.

Singer continues:

In nature, lupines produce plenty of seed, but only a few will germinate and mature. A suggestion that mimics nature’s way: sow plenty of seed to increase your chances. There’s still time to start lupines and other California wildflowers from seed, and [the Theodore Payne Foundation] is well-stocked.

Singer is Special Projects Coordinator for the heodore Payne Foundation. She says the nonprofit native plants organization "is now at the Hollywood Farmer’s Market at Selma and Ivar, Sundays from 8am-1pm, selling plants and imparting information." She used to live in Echo Park.