No sound is played when a Flowering Dragon Fruit entity successfully plants Dragon Roots. This includes when a Flowering Dragon Fruit plants Dragon Roots when it hits a block, when it has rolled too far, or when it is hit by a player/destroyed in another way. If a Flowering Dragon Fruit is stopped in any of these ways, but fails to plant Dragon Roots, it does play a sound. This is inconsistent with non-flowering Dragon Fruit entities, which always play a sound when stopped.