Peonies are cherished garden staples known for their extravagant, large blooms and long lifespan, often thriving for decades in one location. Their impressive floral display in late spring and early summer is a direct result of the care they receive during the initial awakening period of the season. Spring maintenance is the most influential time for determining the quality and quantity of flower production. Focusing on specific practices as the weather warms ensures plants develop the strength needed to support a spectacular flush of color.
Post-Winter Cleanup and Inspection
As the soil begins to thaw and new growth emerges, the first step is a thorough cleanup of the area surrounding the plant crown. Removing remaining winter mulch, fallen leaves, or last season’s debris improves air circulation at the base of the plant. This debris can harbor overwintered fungal spores, posing a significant threat to vulnerable new shoots.
Look closely for the emergence of growth buds, often referred to as “eyes,” which appear as reddish or pinkish points pushing up from the root crown. Visually inspect the emerging stems for signs of damage, such as blackened tips or soft, wilted areas, which could indicate the early onset of disease. Promptly removing suspicious material helps reduce the inoculum load for the entire growing season.
Proper Feeding for Vigorous Growth
Peonies require specific nutrient ratios in the spring to fuel rapid growth without sacrificing flower production. The ideal fertilizer profile is low in nitrogen (N) and higher in phosphorus (P) and potassium (K), such as a 5-10-10 blend. Excessive nitrogen encourages lush, leafy growth at the expense of blooms, resulting in a large, green plant with few flowers.
Apply this slow-release granular fertilizer early in the spring, just as the reddish shoots begin to emerge. The nutrients should be scattered lightly around the plant’s drip line—the area just beneath the outer edge of the plant’s future foliage. Avoid placing the fertilizer directly onto the root crown, as this concentration can cause chemical burn or encourage crown rot. Bone meal is a beneficial slow-release option that supplies phosphorus and calcium, promoting strong root development.
Providing Necessary Support Structures
Herbaceous peonies, particularly those with heavy, double-petaled blooms, are prone to “flopping” or bending to the ground, especially after significant spring rain. Installing a support structure early in the season must be completed before the stems reach their full height. Waiting until the plant is fully leafed out or budded makes installation difficult and often results in stem breakage.
Grow-through supports, like metal hoops or cages with a grid, are effective because the stems grow up naturally through the openings. This method provides subtle, comprehensive support for the entire clump. Alternatively, “corralling” uses stakes and twine placed around the perimeter to contain the plant. Ensure the structure is placed away from the fleshy root crown to avoid damaging the plant’s underground storage organs.
Managing Common Spring Pests and Diseases
The cool, damp conditions of early spring are conducive to fungal diseases, with Botrytis Blight being the most common threat to peonies. Also known as gray mold, this disease is caused by the fungi Botrytis paeoniae or Botrytis cinerea. It can lead to the blackening and collapse of young shoots or the failure of flower buds to open, known as “bud blast.”
Preventative measures rely on cultural control, starting with ensuring good air circulation around the plant. This is achieved by the initial cleanup and appropriate plant spacing. If you observe infected shoots, remove them immediately by cutting the stem well below the affected area and disposing of the material outside the garden to prevent the spread of fungal spores. Common pests like thrips can be a concern, as their feeding wounds on developing buds create entry points for Botrytis infection. Avoiding overhead watering limits the prolonged leaf wetness that the fungus requires for development.
Hydration Requirements During Spring
Consistent moisture is necessary during the active spring growth period as the plant develops its foliage and sets buds. While established peonies are relatively drought-tolerant, they benefit from deep watering during extended dry spells. Aim to provide the equivalent of one inch of water per week, including any natural rainfall.
When watering, focus the moisture at the base of the plant to ensure the water reaches the root zone. Avoid using overhead sprinklers or spraying the foliage, as wet leaves create an environment favorable for fungal diseases like Botrytis Blight and powdery mildew. Watering deeply but less frequently encourages the development of a strong, deep root system, which helps the plant withstand summer heat and supports the massive blooms.