Purchase a vibrant plant. Look for new growth, fresh green leaves and a stout appearance. Avoid stringy, weak, browning or yellowing plants.
Choose a suitable location in the garden with good drainage. Find a place that is bathed in partial sun. Prepare the ground. Dig the hole almost twice as large as the plant's root ball. Mix some of the soil from the hole with peat moss and compost. Put some of this mix into the hole. Take the plant from its pot and carefully shake loose the roots. Cut any roots that are pot-bound (wrapped tightly around each other). Place the plant in the hole, and be sure the top of the ball is level with the ground. Fill around the plant with the prepared soil and water it thoroughly.
Sprinkle flowering plant fertilizer around the plant's drip line, and then soak the area. Keep the plant watered for several weeks, but do not water if there is rain. Trim off any dead or dying sections, and remove the old flower heads after they have bloomed. Divide and transplant if desired after two or more years.