From Ground: First, water yellow trillium plant to dampen the soil. Then, dig a wide trench around the plant using a spade or trowel, ensuring the plant's root ball remains intact. While lifting the plant from the soil, be gentle to avoid any root damage.
From Pot: Water it thoroughly and gently tip the pot sideways, guiding the plant and its root ball out while protecting with your other hand. If needed, lightly tap on the sides of the pot to loosen it.
From Seedling Tray: Moisten the soil to make it easier to remove each seedling. Using fingers or a small tool, gently lift each seedling by its leaves, not the stem.
Note: In all scenarios, once the yellow trillium is removed, handle it by the root ball to avoid damaging the root system. Keep the plant in a shaded, sheltered area until it is ready to be transplanted.