Performance of Black Diamond™ Crape Myrtle Cultivars in North Texas

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ag Science and Natural Resources

Date of Award

Spring 2018

Abstract

Black Diamond™ (BD) is a new series of crape myrtles with dark burgundy foliage. However, no formal studies exist concerning their landscape performance in Northeast Texas. In this study, plants were established at three different locations, each with unique soils and microclimates: Greenville, TX, (heavy clay/full sun); Campbell, TX, (sandy loam/morning shade, afternoon sun); and Commerce, TX, (clay loam/full sun). Each site was divided into four blocks of six plants containing one green-leaf cultivar, 'Centennial Spirit', and five BD cultivars ('Red Hot', 'Crimson', 'Best Red', 'Pure White', and 'Blush'). Plants were scored on a scale of 0 to 10 with 10 as the best overall landscape performance. Five factors were considered: foliage growth, flower abundance, drought tolerance, disease resistance, and pest resistance. Stomatal conductance, leaf temperature, and photosynthetic rate (A) were measured once during the growing season. All cultivars were susceptible to pests (CMBS) and disease (SM), likely caused by wind, proximity, and soil characteristics. The standard, green-leaf, had numerically higher average A (7.17 µmol CO2 m-2 s-1) and lower average intercellular CO2 (233 µmol CO2 mol-1) than all black-leaf cultivars, however, they were not statistically different, P≤0.05. The standard outgrew all other cultivars with an overall performance score of 7.42 while the best BD cultivar scored at 6.79. Though 'Centennial Spirit' did the best overall, 'Crimson Red' and 'Best Red BD crape myrtles can be recommended as small shrubs for landscapes in North Texas soils.

Advisor

Derald Harp

Subject Categories

Agriculture | Life Sciences | Plant Sciences

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