Blazes only drop rods if they are killed by a player. Botania does not provide any options for "fake player" kills, so even though you can move blaze spawners and keep them active without a player, you will need to use another mod to obtain drops from those blazes.
In general, Endoflames are not a great source of mana, unless you go really wide, and spawners typically aren't particular fast sources of mobs either.