Lyrics:

Day time is weary, and I caw' dusk dreary,
For lasses in missels are rakin the hay.
When kye come for strippin' and ewes come for clippin',
We think on our soldiers now gone right away.
caw' = call
missels (mistals) = cowsheds
kye = cows; strippin' = milking
clippin' = shearing

The courtin gate's idle, no lad flings his bridle
Over the yoke stoup and comes seekin' may.
Wae's heart, but we misses our lads' softest kisses:
The flowers o' the forest have gone right away.
yoke stoup (yat stoup) = gate post
may = flowers of the hawthorn; greenery for May Day
wae's heart = woe is the heart; waly, waly

At Martinmas hirin' no ribbon, no tirin',
Where God's penny's earned, and the time's come for play.
No cheapjacks, no prancin', wi' teamster clogs dancin':
The flowers o' the forest have gone right away.
tirin = attiring, adornment
God's penny = earnest-money; a small sum given to a servant when hired.
cheapjacks = travelling hawkers, with a brisk line of patter

Plough lads from Pannal have crossed o'er the Channel;
Shepherds from Fewston have taken King's pay;
Thackrays from Dacre have sold every acre;
You'll no' find a delver from Haverah to Bray.
have taken King's pay = enlisted as soldiers
delver = quarryman
I thought at first “Thackerays” might be “thackers” (thatchers), but in both versions I have, it's sung as “thack'ries.” Thackeray is a good Yorkshire surname—perhaps this is a reference to a local family?

Many a lass now is weepin for her man that lies sleepin,
No wrap for his corpse but the cold Flanders clay.
He'll ne'er lift his limmers, he'll ne'er wean his gimmers:
The flowers o' the forest have gone right away.