Within reach is not necessarily adjacent. Adjacent is considered next to. In game terms this would imply the hex where you are situated, meaning that there are 6 adjacent hexes/character has 1" reach. Stretching changes reach, but it does not change the definition of adjacent. Using Growth, the character has a bigger footprint, giving more area to be adjacent to, and also increasing his reach. But nowhere does that change the definition of adjacent to anything that can be reached.