Tree peonies, unlike their herbaceous counterparts, are woody shrubs that do not die back to the ground each winter. Their stems persist through the cold season, with new growth emerging from these established frameworks in spring. This allows them to grow larger and more stately over time.
Distinctive Features of Guardian of the Monastery
The ‘Guardian of the Monastery’ tree peony is a remarkable cultivar known for its flamboyant, large blooms, typically 8 to 10 inches across. Its flowers exhibit a captivating blend of cream, pink, and lavender, often fading to white at the edges. Dark purple flares at the center provide a striking contrast. These single to semi-double flowers are gracefully held above the foliage. This mid-season bloomer can reach 4 to 5 feet tall and 3 to 4 feet wide, developing a slight floral fragrance.
Planting and Site Selection
Selecting the right location is important for ‘Guardian of the Monastery’ tree peony, as these plants do not transplant well once established. An ideal site provides well-draining soil with a neutral to slightly alkaline pH, ideally between 6.5 and 7.5. Incorporating organic matter, such as compost, enriches the soil and improves drainage, as tree peonies cannot tolerate waterlogged conditions. While tree peonies tolerate full sun in cooler climates, they thrive and their blooms last longer in dappled light or a location with morning sun and afternoon shade.
When planting, allow about 5 feet between plants for mature size and air circulation. For grafted tree peonies, plant the graft union (a slight bulge near the stem base) 4 to 6 inches below the soil surface. This deep planting encourages the scion to develop its own root system. After planting, water thoroughly.
Ongoing Care and Maintenance
Newly planted ‘Guardian of the Monastery’ tree peonies need consistent moisture during their first year, requiring deep watering every two weeks in dry periods. Once established, these plants are drought-tolerant, but deep watering should occur when the top 4 inches of soil are dry to prevent root rot. Avoid planting them near automatic sprinkler systems that keep the soil consistently wet. Fertilize in early spring as new growth emerges with a balanced general-purpose fertilizer. Avoid high-nitrogen fertilizers, as they promote excessive foliage at the expense of flowering.
Pruning requirements for tree peonies are minimal. Remove any dead or damaged wood in late winter or early spring. Spent flowers can be deadheaded in summer for a tidy appearance. For shaping or size reduction, some stems can be cut back, but avoid severe pruning as tree peonies are slow to regenerate.
Ensuring Long-Term Health and Addressing Challenges
‘Guardian of the Monastery’ tree peonies are hardy plants, thriving in USDA Zones 4 through 9. They may benefit from winter protection in colder areas, such as mulching the base or wrapping young plants in burlap. While resilient, tree peonies can be susceptible to botrytis, a fungal disease appearing as black areas on foliage, buds, or stems, particularly in cool, wet conditions. Maintaining good air circulation and well-draining soil helps prevent this.
Tree peonies are slow to establish and grow. A newly planted ‘Guardian of the Monastery’ may take two to three years for its first blooms, and several more seasons to reach full flowering potential. Despite this, a well-sited and cared-for tree peony can flourish for many decades, some living for up to 100 years.