good king wenceslas is well known and fits well on the pipes. the words were added to an existing easter carol (13th cent finnish) replacing a prior easter/spring themed song. see this link for what i think is arguably a better song: "it is the time for flowering".
en.wikipedia.org/wiki/Good_King_Wenceslas
Spring has now unwrapped the flowers, day is fast reviving,
Life in all her growing powers towards the light is striving: Gone the iron touch of cold, winter time and frost time, Seedlings, working through the mould, now make up for lost time.