The Field of Boliauns – Creative Problem Solving

One fine day in harvest, Tom Fitzpatrick went strolling along the sunny side of a hedge.
All of a sudden he heard a clacking noise in the hedge before him. Tom tiptoed on, trying to see what was making the noise.
By its side sat a little old man, with a little cocked hat stuck upon the top of his head, and a leather apron hanging before him.
“Amazing!” said Tom to himself, “This must be a Lepracaun; I’m a rich man.
Tom knew very well, that Lepracauns always have a crock of gold buried in some hiding-place or another.
Tom caught the Lepracaun in his hand.
“Tell me where is your gold. Show me this place now!” – shouted Tom.
He looked so wicked that the little man immediately answered: “My pot of gold is hidden only a couple of fields off.”
So they went, and Tom held the Lepracaun fast in his hand, though they had to cross hedges and ditches, and a crooked bit of bog, till at last they came to a great field all full of boliauns.

The Lepracaun pointed to a big boliaun, and said: “Dig under that boliaun, and you’ll find a great pot filled with guineas.”
Tom hadn’t brought a spade, so he took off one of his red garters and tied it around the boliaun, so that he could find the place again later.
Then he said to the Lepracaun:
“Swear to me that you’ll not take that garter away from that boliaun!”
The Leprechaun swore right away that, Faith, he wouldn’t so much as touch it.
“You may go,” Tom said, releasing his grip.
“Goodbye, Tom Fitzpatrick, may what you find do you much good.” – leprechaun said him politely.
Tom ran home, got a spade, and then ran back to the field of boliauns.
When he got there, he realized that Leprechaun outwitted him, although he kept his word and hadn’t touched neither to his garter nor to flower.
Based on a Irish tale “The Field of Boliauns”

What came up with a cunning Leprechaun?