This song is structured like the 12 Days of Christmas in that it builds as the verses progress.
Leader: I'll sing you one ho
Group: Green grow the rushes ho, What is your one ho?
Leader: One is one and all alone and ever more shall it be so.
That is the basic form. Here is the second round:
Leader: I'll sing you two ho
Group: Green grow the rushes ho, What is your two ho?
Leader: Two, two little Cub Scouts, Clothed them all in green ho
Leader and Group: One is one and all alone and ever more shall it be so
So, you can see how it goes. Here are the other 10 lines:
Twelve for the Twelve Apostles
Eleven for the eleven who went to Heaven
Ten for the Ten Commandments
Nine for the night (nine??) bright shiners
Eight for the April rainers
Seven for the seven stars in the sky
Six for the six proud walkers
Five for symbols at your door
Four for the Gospel makers
Three, three the rivals
I'll sing you twelve, Ho (or oh or O)
Green grow the rushes, Ho
What are your twelve, Ho?
Twelve for the twelve Apostles
Eleven for the eleven who went to heaven,
Ten for the ten commandments,
Nine for the nine bright shiners,
Eight for the April Rainers, (or April Showerers, or occasionally Eight for the eight bold Rangers)
Seven for the seven stars in the sky, (or Seven for the seven who went to Heaven)
Six for the six proud walkers, (or brown walkers)
Five for the symbols at your door, (or my door)
Four for the Gospel makers,
Three, three, the rivals,
Two, two, the lily-white boys,
Clothèd all in green, Ho Ho (or Clothe them all in green, oh oh or Dressèd all in green, o o, or "Clad them all in Green, O)
One is one and all alone (sometimes One is one and one alone, One and one is all alone, One is one and stands alone, or One is one and always one)
And evermore shall be (it or as) so.