Azalea is a small bush block that generates inside lush cave biomes and on the surface above them — its appearance on grass usually indicates a lush cave directly below, which makes it a useful indicator for cave-spelunking expeditions. The texture shows compact dark-green leaves with small pink-red blossoms scattered through. The plant can be placed on grass, dirt, podzol, moss, rooted dirt, coarse dirt, mud, or farmland — a wider range than saplings accept.

The most useful interaction is bone-mealing: each application gives the placed bush a 45% chance to grow into a full azalea tree, with a stout oak-like trunk and a canopy of azalea leaves, provided a 3×5×3 area above it is clear of blocks other than leaves and logs. A player-grown tree merely replaces the block beneath its trunk with a single block of rooted dirt — hanging roots and lush caves appear only under naturally generated azalea trees. Azalea never grows on its own without bone meal; applying bone meal to moss blocks in lush caves can sprout new azalea bushes, making the plant renewable. The block is harvestable by hand and stacks normally in inventory.