A giant bird of paradise plant (Strelitzia nicolai) can grow to a height between 15 and 30 feet and width of 15 feet. Compare this to a regular bird paradise plant that only reaches about 5 feet in height, and you understand why it is called "giant." Whether you are having difficulties with your giant bird of paradise plant, or it's time for a change, the best method to get rid of it is by physically removing it from your garden or yard.
Wait until the soil is mostly dry to get rid of your giant bird of paradise plant. Drier soil is usually easier to cut through than extremely wet soil.
Cut down your giant bird of paradise. Use a hand saw or chain saw, and cut it down to about 12 inches above the ground. You will then have room to dig and still have part of the plant to grip to pull it out of the soil.
Start to dig a circle around your giant bird of paradise plant with a spade. Dig about 12 to 18 inches, and cut in under the root ball. Try to get as much of the roots as possible, so adjust your digging depth and width as you feel the roots. Use a spade, pick ax or reciprocating saw to help cut through the roots (you won't be able to get them all).
Push down on the handle of the spade near the bottom to lift the giant bird of paradise out of the soil. Be careful not to break the handle. Pull up on the plant as well. You can also rock the plant back and forth to help free it. You can also tie a rope around it and pull it out with a truck. Use common sense and prioritize your safety and integrity of your tools and truck over removing the plant. If necessary, call in a tree remover specialist.
Take the plant out of the hole and shake off the excess soil. Discard the plant, and fill your hole back in. A giant bird of paradise should not grow back if you got the bulk of the root ball.