The Karl Rosenfield peony is a popular and classic variety known for its large, double flowers and rich, deep red color. Here are some key points about this peony:

1. Appearance: Karl Rosenfield peonies produce large, fully double flowers with a lush and rounded form. The blooms typically measure 6 to 8 inches (15 to 20 cm) in diameter and feature numerous layers of petals that create a full and luxurious appearance. The flower color is a deep, vibrant red, which contrasts beautifully against the dark green foliage.

2. Size: This peony variety typically grows to a height of 2 to 3 feet (60 to 90 cm) and spreads to a similar width. It forms a dense, bushy clump of foliage that provides an attractive backdrop for the showy flowers.

3. Blooming Season: Karl Rosenfield peonies bloom in late spring to early summer, usually around May to June, depending on the climate and growing conditions. The flowers are long-lasting and make excellent cut flowers for floral arrangements.

4. Sun and Soil Requirements: Karl Rosenfield peonies prefer full sun to partial shade. They thrive in well-draining soil with good fertility. It's important to avoid planting them in areas with poor drainage, as they are susceptible to root rot.

5. Watering and Maintenance: Peonies have relatively low maintenance requirements. They prefer regular watering, especially during dry periods, but they can tolerate some drought once established. Deadheading spent flowers can help promote continued blooming, and removing faded foliage in fall helps prevent disease overwintering.

6. Landscape Use: Karl Rosenfield peonies are versatile plants that can be used as specimen plants, in borders, mass plantings, or mixed perennial gardens. Their large and vibrant flowers add color and visual interest to the landscape, making them a favorite among gardeners.

Overall, Karl Rosenfield peonies are prized for their stunning flowers, rich color, and ease of care. They are considered one of the most reliable and beautiful peony varieties, making them a popular choice for gardens and floral displays.