Hi Molly. Welcome to ATP! I hope someone with a clue ABOUT California Bluebell sees your post.
I didn't know, either, but I know that many perennials are more complicated to start from seed than most annuals.
I see two related plants in the database that might be your bluebells:
California Bluebells (Phacelia campanularia)
and
Californian Bluebell (Phacelia viscida 'Tropical Surf')
Sorry, only the first has a photo! And I never heard of the genus Phacelia. I wonder which forum would specialize in that?
@Chelle said this in the database about Desertbells (Phacelia campanularia):
Comment: w/sown 1-20-14, sprouts 5-7-14 batch #2 cool and dark, 4-4-14 (note changes in DB if found), pos. germ., 4-7, sown in one plastic, sprouted 4-9 batch#3 cool and dark 4-7, sprouts 4-10
Note: seeds will sprout in light or dark.
@SugiGirl might raise them form seed; she offers seeds as trades.
If one has no idea how to start a seed, but it's likely to have some kinds of dormancy, "wintersowing" is one guess for how to start it. And I see that's what Chelle did.
In a jug or plastic tray with clear lid, lay down some good seed-starting mix or coarse vermiculite, and moisten it.
Sprinkle seeds.
Often tiny seeds prefer to be on the surface and see some light while they decided whether to break dormancy. You might split the difference and cover them with a VERY THIN layer of medium vermiculite, so they still see the light but are barely covered, in case they want a little covering.
Now, the weird thing about wintersowing is that you seal the jug or tray so rain doesn't drown it, and it doesn't dry right out, then
put that thing outdoors in mid-winter, in enough shade that a sunny day doesn't make it TOO warm!
The plastic keeps insects and slugs away. The clear lid gives it a little more warmth and uniform humidity. The natural day-night cycle and cold-and-warm-spells provide the natural "stratification" that breaks most forms of dormancy.
Come early spring, start watching for sprouts. You may have to prop the lid open for a week or two, but when the seedlings are 1-2 inches tall, either prick them out and transfer to 4" pots, or maybe plant them right out if the soil is warm enough. Some winter-sowers don;t prick out individual seedlings into pots, they plant entire CHUNKS of seedlings and let the strongest ones win.
But wintersowing might be more work than bluebells need. Even seeds needing cold-wet stratification CAN be started on coffee filters in baggies, in the fridge for a few weeks, then germinate as normal seeds. They call that the "Deno method", and it works even if you have a dog that would chew up any wintersowing jugs you put outside.
P.S. When wintersowing, consider that your jugs or trays might blow away.
If they are covered with snow for a few months, no problem. The wintersowing theory is that "seeds are used to that and know when to sprout". The plastic just gives them extra warmth and protction so they sprout ASAP and then are protected.