In September I planted heirloom Stevia (Stevia Rebaudiana) in the cinder blocks that form the raised lettuce beds. To date, I have nada. Zip. Zilch. I have since learned that Stevia is difficult to germinate from seed. No kidding. With absolutely no production at all I can only give Stevia a very bad rating in Zone 8-9. If you feel like growing it, try to find a plant to transplant into your garden.