Yes you can transplant from the ground and to a pot. Cut a large circle around the plants base. You wanna take some of this soil its in and the root ball at the same time.

The plant may go through a short stress period. He will look droopy because of minor root damage. Place him in a shady area and water him. Maybe spray the foliage with a bit of water.

He should come back to normal in a few hours or overnight.

Then you can take him wherever to flower and collect pollen. Just remember this is a Wind Pollinated Plant. So take it downwind