Hi, I am from New Zealand and have Tagasaste growing in my garden. I have been germinating seeds for a number of years. It is indeed tempermental to germinate but I have worked out the best way is to soak in hot water for as long as it takes. The black seeds will swell up and turn green when they are ready to plant. I leave the seeds in the water, and replace the water every day with new hot water. I do not scar them just soak, and remove them as they plump up.
Without doing this, they can still germinate but the seed shell will be to rigid to let the sprout out and can choke the head of it. This seems to mainly only be the case for old seed, if you sow fresh seed from the plant it can just be planted directly into soil.
Hope this helps.
I have mentioned this plant to a few people in the USA and in Canada, hopefully they can find seed. I may give them the contacts on this site.
Thanks.
