Where can I buy it.

i am crap at latin names and dont know what plant you mean.have you considerd someone like chiltern seeds.maybe propergate your own if you have know luck.

Try Yerba Buena Nursery. somewhere in California.

Hi Posie. You can (with difficulty) get the D. rigida in this country but the island version that you are after is virtually impossible. I would love a decent tree poppy but no chance. You might do better if you ask advice on Dave's Garden or another US forum. This forum is based in the UK and although good advice is given internationally it is difficult to advise people where to buy plants when they are really dedicated to one country (or in the US case nearly only one State.)