I googled it and found out it wasn't nonsense after all.
Smart Set commented on 09.14.05
Why certainly! I suppose it's rather poetic Italian... Basically, the mattress is singing lightheartedly to the tree in praise of its wonderful shade: "Never such shade was..!" He continues: "...di vegetabile, cara ed amabile, soave più." He has a beautiful voice and is accompanied by a full baroque orchestra to the tune of Handel's "Largo".
Rebecca commented on 09.14.05
Can you explain Ombra Mai Fu? I would think it means every literary variable with a meditative brassiere, but that's just me.