The ceremony is conducted in much the same way as other unity ceremonies are. You set up a separate table near the alter.
On this table you would have a potted tree/sapling, something perhaps with special meaning to the couple or taken from a special place.
You would also have two small buckets of dirt, two gardening trowels as well as a small watering can placed on the table.
If you choose to have the ceremony symbolize the joining together of both family’s then upon the entrance of the mothers, each mother goes to the table and scoops in a small amount of dirt. Then they take their seats.