All your young plants should be brought in. I err on the side of caution with all of my plants. Even my citrus are not allowed to experience weather below 40°F. I want my plants to grow, mature, and fruit as quickly as possible. Even if temperatures in the 30s would not kill a plant, it could cause it to go dormant. Whereas, my jaboticabas have fresh new growth flushing out even after I've moved them inside for the winter.