The text is by Franz von Schober, whose songs (like Die Forellen) often have raffish undertones. A snowdrop rings its bell to announce that Spring is on its way. The viola leaps awake, adorned as a bride in "den Mantel sammetblau, Nimmt das güldene Geschmeid, Und den Brilliantentau" (in a blue velvet cloak, adorned with gold and dew like diamonds). But it's not Spring yet. No bridegroom, no sister flowers. The viola hides, ashamed. Soon, roses, tulips, hyacinths and lilies come out in their finery but it's the humble viola whom Spring calls his "favourite child". The flowers are sent to search her out. (How Disney would have illustrated this!) The viola is found, her head buried beneath her leaves. It's charming, but any gardener knows roses and lilies don't come out til much later. Or walk. Or think about bridegrooms. This is not a nature song!
Be charmed, too by Hugo Wolf's setting of Eduard Mörike's poem Zitronenfalter im April (HERE) and Karwoche, where violets are portents of death (HERE)