It's best to use hanging-basket plants that have long stems.
What You'll Need:
Remove the plant from its pot. With your hands, split it in half gently, then split each half in two; each quarter will make 1 topiary.
Plant 1 quarter in the new pot, tamping the soil firmly around the roots.
Gather ivy stems, and carefully feed them through the topiary form; for flat forms like the circle, this step isn't necessary.
Push the stakes as far as possible into soil.
Divide stems according to the form. (Andrew made 4 groups, 1 for each obelisk leg. For flat forms, make 2 groups.)
Beginning with the longest stem in each group, wrap it gently, clockwise, around an upright wire on form. If stem is longer than wire, train the rest down the opposite wire.
Wrap next stem counterclockwise. Repeat, alternating between clockwise and counterclockwise, until stems are used up. If part of form is full, wind remaining stems around less-full wires.
For a neat look, trim any side shoots that are too small to train.
Repeat to make 3 more topiaries.
Water thoroughly, and place in bright, indirect light. As topiaries grow, train stems onto form or prune off excess growth.