To get your plants into the planting holes, you're going to need to squeeze or stretch the root ball. Try not to rip off or damage the roots. Instead, gently massage the root ball into a more tubular shape. It's OK if the soil falls off, but try not to tear off roots.

It's usually easier to plant from the outside of the pot in, inserting the roots through the planting hole and grabbing them inside the pot.

However, if your plants are small enough and have a large root ball, you may opt to feed the foliage through from the inside of the pot.