Established Peony Has Failed to Bloom

I have an established peony bush that has not bloomed in the past two years. It is growing in the sun and no soil has been added to bury the roots deeper. It used to bloom profusely. Any ideas?

Overfertilization or fungal disease can prevent peonies from blooming. Avoid high nitrogen and regular fertilization that can give you lush green growth and no blooms. Though peonies can stay in the same location for many years, your plants may benefit from transplanting. Dig and divide the plants in fall as the leaves yellow or after a frost. They may not bloom until the second spring. The fungal disease, botrytis blight, can prevent peonies from blooming. Infected plants develop buds that turn brown and never open. Removal of infected buds and diseased leaves as they appear, a thorough clean up in the fall, and a little dryer spring weather will help keep the disease in check.