I'm in zone 9b, Santa Cruz, CA. We are 1 mile from the coast, so weather usually doesn't get too hot or too cold. I have very sandy soil. I started H. Tamniodes seeds from Fedco last March, after cold storage in fridge and freezer. I had very good germination rates, and many tiny seedlings, but lost many in moving to pots. By winter, I had about six seedlings go dormant. In March 2021, I planted them out to two locations. One is almost full shade, the other gets morning sun, against a wall. The plant in the sun location is doing well and is now two feet and growing with lots of sprouts at the base. The plant in shade is still only 1inch. I don't see anyone in my zone reporting any success, so I'm adding my experiences with this plant. I'm hoping I will be able to continue growing it here!
