Although the ambergris fruit did not sound rare, it was actually very rare. This was because a blue-eyed white dragon could not always sleep in one place. If the ground could not be nourished by the ambergris for a long time.., then it would be impossible to grow a plant of the ambergris fruit.
Therefore, the plant of the ambergris fruit needed to be in a place where a blue-eyed white dragon would sleep for a long time before it had a chance to breed.
Another point was that once the green-eyed White Dragon woke up and found the plant of the dragon saliva fruit, it would definitely destroy it at the first opportunity, because no green-eyed white dragon would want others to know that it was drooling in its sleep, moreover, it would be first-rate for hundreds or thousands of years!