Is it this one by Edward Thomas? Its a favourite of mine
If I Should Ever by Chance
If I should ever by chance grow rich
I'll buy Codham, Cockridden, and Childerditch,
Roses, Pyrgo, and Lapwater,
And let them all to my elder daughter.
The rent I shall ask of her will be only
Each year's first violets, white and lonely,
The first primroses and orchises
She must find them before I do, that is.
But if she finds a blossom on furze
Without rent they shall all for ever be hers,
Codham, Cockridden, and Childerditch,
Roses, Pyrgo and Lapwater,
I shall give them all to my elder daughter.
The point of the blossom on furze line is that you can almost always find blossom on furze which is why another saying is "When gorse(furze) is in bloom, kissing's in season.