This example is for when the whole rootball of the plant is cut / split up, the plant being used is lemonbalm.(Other examples that this works with are tansy, chives, grass).
It is usual to do this in autumn or spring, like in the example above, the plant has shrunken down to the ground, but there are plenty of roots underneath ready to be split.
Dig around the roots.
Lift up the plant.
Use a spade or fork to split into as many plants as you would like. Sometimes, if it is a really tight root ball, two spades or forks will have to be used, back to back to cleave.
Here is a little lemon balm plant ready to be planted:
Plant in it’s new home, or in a pot. One of the splittings can be planted in the original spot.
Here it is the next season: