I have tried four times to grow an embothrium from a rooted cutting. The new leaves come fine but soon become yellow and drop off. The whole thing never gets that healthy vigour. Mostly I do them in multi purpose compost, and have tried the greenhouse, outside, and now in a cool hallway. What conditions should an embothrium have?
Then scrape back the soil and ascertain that it has a fair amount of roots and cut it connection to the parent plant. But leave it in the ground to recover for a year until it develops its own root system before moving it in September.