I transplanted a Bird of Paradise 5-7 years ago and it's stunted!

Without enough space to grow to maturity, plants become overcrowded and may give lackluster flowers. When planting, be sure to provide enough room for the mature plant size and not just for the size of the young plant. If a plant outgrows its space, you can cut a wide circle in the soil, severing the roots, and transplant to a more spacious area of the garden. As plants grow, they slowly multiply and might require division to give the plant more room. You simply dig up the plant and divide the root ball into several sections. Return one section to the original planting space and plant the other sections to a new area of the garden. Give the divisions as gifts or add them to your compost pile if you don't have room for more plants in your gard