Can anyone tell me about sprouting comfrey from seeds?
How long does it take? Does it need any special treatment such as
stratification?

Assuming you have viable seeds they do require stratification/winter chill and I have been reading that it can take up to 2 years to see germination.
(I cheated and bought plants instead!)

Oh dear-I started seeds ,but did not chill.
Into the 'frig they go---I wonder for how long they need chilling?

The seed box was in the 'frig (not freezer) for about one month.
Then out to south window over the summer from mid June until September.
Box has been watered sporadically, and since nothing was happening--
I was going to toss it.
Surprise! Surprise! there are three seedlings there now in September!
I guess that I will grow comfrey as a houseplant over the winter.

Good news!!

Tom Clothier says:
"Symphytum officinale, and tuberosum ,
Sow at 20ºC (68ºF),
if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks

Karen

Way to go, Caroline!

Now, I have heard that there are some new variegated cultivars of Comfrey?
Does anyone know of a source for seeds of the variegated ones?
Canada Customs frowns on us bringing in plants so I need to source seeds.

Canadian suppliers shy away from Comfrey because there is a ban on some medicinal preparations of it-especially those for internal treatments. Comfrey contains chemicals which can damage liver function.

I've never seen commercially available comfrey anywhere near here.

Have you tried Richters? I thought I saw they were now specializing in medicinal herbs, and may even have changed their name (or perhaps opened a new division?) Added bonus is they are based in CA

Most comfreys in the trade are sterile or close to sterile, hence the difficulty of procuring seed.

Yes, I had heard of the sterility problem.
But, I was hoping, perhaps one of the new colored cultivars would produce viable seeds.
Maybe when one of the big seed companies gets hold of them?