Come Mayday, the radio in Ireland always plays (about a million times) a Catholic hymn that has always seemed utterly pagan to me. It goes:

Bring flowers of the rarest,
Bring blossoms the fairest,
From garden and woodland and hillside and dale;
Our full hearts are swelling,
Our glad voices telling
The praise of the loveliest flower of the vale.

O Mary, we crown thee with blossoms today,
Queen of the Angels and Queen of the May,
O Mary, we crown thee with blossoms today,
Queen of the Angels and Queen of the May,
Their lady they name thee,
Their mistress proclaim thee,
Oh, grant that thy children on earth be as true

As long as the bowers
Are radiant with flowers
As long as the azure shall keep its bright hue.
O Mary, we crown thee with blossoms today,
Queen of the Angels and Queen of the May,
O Mary, we crown thee with blossoms today,
Queen of the Angels and Queen of the May,

Sing gaily in chorus,
The bright angels o'er us
Re-echo the strains we begin upon earth;
Their harps are repeating
The notes of our greeting,
For Mary herself is the cause of our mirth.

and you can hear it here, in rather a
sugary version

It's also available on a CD called Faith of Our Fathers, which has all those old Irish Catholic hymns.