Fascinating topic. I went through a phase where I wanted to grow Protea. In Florida. I know. Dumb idea. And no it didn't work. They all succumbed to fungus from humidity. But I was successful in germinating several flats of seeds of different species before I killed the plants. And the one ingredient necessary to germinate Protea and Banksia seeds? FIREWATER. Literally. Water that has soaked through the ash and embers of burnt plant material from wildfires. That is how the seeds are germinated in Australia and South Africa in the wild. The seeds are so hard and so tough, evolution has decided that they have go through the fire themselves to weaken the outside, then the firewater leaches in and provides certain chemicals that trigger germination. Each packet of seeds I got from South Africa gave specific directions for making the firewater, and scarifying the seed in absence of a wildfire at your location. It was one of my more memorable adventures in gardening. But I was warned during master gardner lectures years ago not to use ash in the garden here, because the soil is already acidic from leaf mold from mainly oak and pine detritus. And never under any circumstance should anyone anywhere use ash from their charcoal grill from briquets.
