Peonies are a common flower in the garden and can be used as focal point or to create a hedge. They come in a variety of colors and shapes such as single, semi-double, double, Japanese and anemone. Peonies are sensitive to fertilizer but can still benefit from the proper application of it. With proper use, fertilizer can help peonies live long and healthy lives.
What Are Peonies?
Peonies are perennial plants that produce large flower heads in the spring. They are long-lived, able to live 50 years or more with good care. Peonies can either be tree-like shrubs that do not die back each year or the garden variety that reach about 36 inches tall and do die back each year. Typical colors are white, pale yellow, pink, rose and red.
When Do Peonies Need Fertilizer?
Peonies prefer acidic soil with a pH of 6.0 to 7.0. If you are uncertain as to the pH of your soil, have a sample tested. Once you have your results, you can add fertilizer in the spring for fall planting. Once the soil pH has been adjusted and the peonies planted, additional fertilizer should not be needed for 1 to 2 years. After that, annual spring applications should be sufficient to produce healthy plants and blooms.
What Blend of Fertilizer to Use
A low nitrogen fertilizer is recommended for peonies. Nitrogen is the first number listed in the formulation. A mix of 5-10-5 or 5-10-10 is suitable for peonies. They can also benefit from an occasional feeding of bone meal or some form of phosphate. It stimulates strong root growth and flower set.
Caution with Fertilizer
Peonies are very susceptible to fertilizer burn. This is caused when the fertilizer comes in direct contact with the roots or the plant itself. When preparing new beds for planting peonies, add ¼ to ½ cup of fertilizer and mix it in with soil at least 1 foot deep. Going deeper to about 3 feet will produce better results. This adds the necessary nutrients to the soil but keeps them far enough away from the plants and it roots to prevent damage. For established plants, keep fertilizer 6 inches away from crown and do not get any on the leaves as you distribute it. Use ¼ cup per plant just after flowering and scratch it into the soil.
Other Care Tips
Use organic mulch in the spring to control weeds and help keep moisture in. Remove mulch in the fall to prevent the spread of fungal disease. Cut the flower stems back to 3 inches in height after the first fall frost to prevent overwintering of fungal disease or pests. Practice debudding, the removing of all but the terminal bud on each stem as soon as buds are visible, to promote large flowers. Stake peonies to help them support the weight of large blossoms.