The Lagerstroemia genus, commonly known as the Crepe Myrtle, is a group of deciduous trees and shrubs known for their vibrant summer color and attractive winter structure. These plants are staples in warm temperate landscapes due to their long blooming period and adaptability. This article focuses specifically on the ‘Osage’ cultivar, a variety offering unique characteristics and resilience.
Unique Characteristics of the Osage Crepe Myrtle
The ‘Osage’ Crepe Myrtle is a hybrid of the common Crepe Myrtle (Lagerstroemia indica) and the Japanese Crepe Myrtle (Lagerstroemia fauriei). This parentage provides cold tolerance, extending its reliable growing range into USDA Hardiness Zone 6. The mature size of ‘Osage’ is modest, reaching an average height of 12 to 18 feet with a similar spread. It typically forms a semi-pendulous, vase-like crown.
The floral display presents as large, loose panicles of light pink blooms, sometimes carrying subtle hints of peach or coral. These ruffled flowers appear reliably from early summer through the fall, providing sustained color. The hybrid’s genetic makeup confers high resistance to powdery mildew, a common fungal disease affecting many older varieties, making it a low-maintenance choice.
A distinct feature of this cultivar is its exfoliating bark, which is appreciated during the winter months. The smooth, shedding bark peels away in thin strips to reveal underlying patches of cinnamon red and chestnut brown. This mottled trunk texture provides year-round appeal. The foliage displays a glossy, dark green hue in summer, turning to shades of red and orange in the autumn before dropping.
Optimal Site Selection and Growing Conditions
Selecting a proper planting site is the first step in successfully growing the ‘Osage’ Crepe Myrtle, as it directly impacts flowering and health. This cultivar demands a location that receives full sun, meaning a minimum of six hours of direct sunlight daily. Insufficient sun exposure results in sparse flowering and can increase the plant’s susceptibility to fungal issues.
The tree is adaptable regarding soil type but thrives best in a well-drained, slightly acidic medium (ideally pH 5.5 to 6.5). While it tolerates various soils, including clay, standing water is detrimental and leads to root rot. When planting, dig a hole two to three times wider than the root ball but no deeper. Ensure the top of the root ball is level with or slightly above the surrounding soil grade.
After planting, apply a layer of organic mulch, such as shredded bark or wood chips, around the base of the tree. Mulch helps regulate soil temperature and retain moisture. Planting in late fall or early spring allows the roots to establish before the stress of summer heat or winter cold.
Essential Maintenance and Pruning Techniques
During the establishment phase (the first two growing seasons), the ‘Osage’ requires regular and deep watering. Providing water once or twice weekly, especially during dry weather, helps encourage a strong, deep root system. Once the tree is fully established, it exhibits good drought tolerance, though deep watering during extended dry spells promotes better flowering and health.
Fertilization is often unnecessary for mature Crepe Myrtles, as overly rich soil can lead to excessive foliage growth at the expense of blooms. If the soil is poor or the tree is newly planted, apply a slow-release, granular fertilizer formulated for trees and shrubs. Apply this in early spring before new growth begins. A balanced formulation that is not high in nitrogen is recommended to support flowering.
Monitor for common pests like aphids, which can be managed with a strong spray of water or horticultural soap. Pruning is best performed in late winter or very early spring while the tree is dormant, before new growth emerges. Since Crepe Myrtles bloom on new wood, pruning at this time will not sacrifice summer flowers.
Structural pruning is the most beneficial approach, involving the removal of dead, crossing, or inward-growing branches to improve air circulation and shape. Suckers, which are shoots emerging from the base or roots, should be removed completely at the point of origin. Avoid the severe topping practice, often termed “crepe murder,” as this disfigures the tree’s natural structure and creates weak branching.