The Texas state flower, the bluebonnet, encompasses all six of the Lupinus species native to Texas. The most widespread and popular bluebonnet, Lupinus texensis, is a winter annual that produces violet-blue (violet-blue group 96A, Royal Horticultural Society Colour Chart) [Royal Horticultural Society (RHS), 1982] racemes in early to mid-spring and is predominately self pollinating. The Texas Department of Highways uses this species widely for floral displays along roadsides throughout much of the state (Andrews, 1986). Rare pink and white variants exist in native populations and a breeding project was initiated in 1985 to develop bluebonnets with novel flower colors for use as bedding plants. 'Abbott Pink' was the first seed-propagated cultivar to be developed from this program (Parsons and Davis, 1993). The second cultivar, 'Barbara Bush' with novel lavender shade flowers was developed more recently (Parsons et al., 1994). As with the cultivars previously developed, we have used recurrent phenotypic selection for maroon flower color to develop 'Texas Maroon.' This cultivar is intended for use as a bedding plant.

Breeding History

In the spring of 1988, Parsons and Grant were inspecting a production field of 'Abbott Pink' bluebonnets in LaPryor, Texas. Grant discovered a plant with a variant color of purplish maroon. To our knowledge, this novel flower color had never been previously observed. Seed was collected from this plant and the seed was used to produce transplants which were planted in the fall of 1989. This planting produced a population containing ~10% maroon-flowered plants with most of the population being a pink or purple hue. The plants with purple or pink flowers were rogued as soon as their color was visible. Seed was collected in the spring of 1990 from the remaining maroon - flowered plants and this seed was used to produce transplants which were planted in the fall of 1990. Recurrent phenotypic selection for maroon colored flowers was repeated for five more years (one cycle per year) until a pure maroon-shaded population was obtained. This line has been grown in isolation for two additional years and is now being released as 'Texas Maroon.' Seed collected from 'Texas Maroon' will remain pure if plantings are isolated from other bluebonnets and off-colors are rogued immediately after flower color becomes apparent.

Cultivar Description

Germination occurs in the fall with young plants forming a dense rosette and then blooming the following March or April. The bloom period is 3 to 5 weeks with plants producing 100 to 200 racemes/m2 ground surface. The racemes, which are mildly fragrant, are maroon in color on the front side of the banner and keel (RHS greyed-red group 179A) and red on the backside of the banner (RHS red group 53D). Flower color hue can vary under changing temperatures. The racemes are 8-12 cm long racemes, 2-4 mm in diameter containing 25-40 flowers. The last racemes produced during the season tend to be shorter than the first ones. Each flower is 1-2 cm long, has a 3- to 6-mm-wide white banner spot in the center of the banner petal and has a pedicel 6 12 mm long. The banner spot often turns to reddish purple (RHS red-purple group 61AB) with age, but the flowers sometimes shrivel before the color change occurs. At full bloom, the plants are 30-50 cm tall, 50-70 cm in diameter, and have a mounded form. The foliage is yellow-green (RHS yellow-green group 146B) and is composed of alternate, palmately compound leaves generally with five leaflets (occasionally six). Individual leaflets are oblanceolate, 3-5 cm long, and 12-16 mm wide at the widest position. Petioles are 4-6 cm long. Seed pods (30-50 mm long and 6-10 mm wide) become visible about one month after anthesis, are densely pubescent and contain four to seven seeds each. Weight per 100 seeds is ~3.5 g. Seeds are light brown occasionally speckled with black.

Performance

Except for having a different flower color, the garden performance of 'Texas Maroon' is nearly identical to the native violet-blue bluebonnet and the previously released 'Barbara Bush' (Parsons et al., 1994) and 'Abbott Pink' (Parsons and Davis, 1993). Plants have been grown from seed in the greenhouse and successfully transplanted outdoors at the following diverse Texas locations: San Antonio (7 years at several sites); Dallas (2 years); Fredericksburg (2 years); and El Paso (2 years). Comparative trials at these locations revealed no differences in garden performance between 'Texas Maroon,' the native violet-blue bluebonnet, and the previously released 'Barbara Bush' and 'Abbott Pink.'

Limitations

Seed must be scarified to obtain optimal germination (Davis et al., 1991). Concentrated sulfuric acid applied for 30-60 minutes is generally satisfactory for scarification. Irrigation or rainfall is needed for germination, but once plants are established, they require little additional irrigation under central Texas conditions. 'Texas Maroon' also grows well in most soilless media. Damping off (organism not yet identified) can be a problem during seedling production but can be controlled effectively with Terrachlor. The plants overwinter in U.S. Dept. of Agriculture hardiness zones 8-10 (U.S. Dept. of Agriculture, 1990) and often survive in zone 7b. Vernalization is not required for flowering.

Justification for Release

'Texas Maroon' is a novel flower color that does not exist in natural populations. The maroon flower color will expand the color palette available for ornamental plantings of bluebonnets.

Literature Cited

Andrews, J. 1986. The Texas bluebonnet. Univ. of Texas Press, Austin.

Davis, T.D., S.W. George, A. Upadhyaya, and J. Parsons. 1991. Improvement of seedling emergence of Lupinus texensis Hook. following seed scarification treatments. J. Environ. Hort. 9:17-21.

Parsons, J.M. and T.D. Davis. 1993. 'Abbott Pink' bluebonnet (Lupinus texensis Hook.). HortScience 28:65-66.

Parsons, J.M., T.D. Davis, S.W. George and W.A. Mackay. 1994. 'Barbara Bush' bluebonnet (Lupinus texensis Hook.). HortScience 29:1202.

Royal Horticultural Society. 1982. Royal Horticultural Society colour chart. Royal Horticultural Society, London.

U.S. Dept. of Agriculture. 1990. Plant hardiness zone map. Misc. Publ. 1475 Agr. Res. Serv., Washington, D.C.