Once you know peonies, you always want them in your garden. This easy-care perennial shrub provides lush, green foliage all summer, with large, fragrant blooms in the spring that make great cut flowers. Peonies are hardy plants that can withstand cold winters and hot summers and keep on growing. Just provide adequate food and water for your peonies and they will give you year after year of gorgeous blooms with the minimum of maintenance.
Peonies grow by means of a rhizome, or tuber. They require well-draining soil, so the addition of soil amendments like compost or sphagnum peat moss will help to keep their roots from developing rotting problems. They prefer a soil pH of 6.0 to 7.0, according to North Carolina State University horticulturist Erv Evans. Ants may gather over the peony flowers; they neither hurt nor help peony blooming. The ants are attracted by the sweet substance produced by the flower buds. Peonies colors are available in white, pink, red and magenta.
Plant so that the "eyes" of the rhizome are no more than 2 inches below the soil surface. A handful of bone meal in the bottom of the hole gives peonies additional food for establishment of new plants. Spread a layer of mulch at the base of plants to retain water over the summer, but remove it in the fall to prevent soil diseases. Peonies do best in cooler weather and are hardy in USDA plant hardiness zones 3 to 8.
Though it may seem that peonies grow on their own without intervention, they do require regular fertilization. Fertilize plants in early spring when the new shoots begin to emerge. Use ¼ cup of 10-10-10 fertilizer per plant worked into the soil near the crown of the plant. The numbers on the fertilizer packages indicate the percentages of the amounts of nitrogen, phosphorus and potassium in the formula. A 10-10-10 fertilizer has an equal amount of these three components, which is often called a "balanced" fertilizer. Avoid putting the fertilizer within 6 inches of the crown, which is very susceptible to fertilizer burning. Water after application to allow the food to soak well into the soil around the root system.
Peony Food and Blooming Problems
Peonies require the right amounts of food to bear their abundant flowers. Application of fertilizers with high percentages of nitrogen will grow foliage at the expense of bloom production. Deficiencies of phosphorus and potassium can also affect peony blooms, according to the University of Rhode Island site. Competition for food and water from the roots of nearby plants can also affect flower production.