Ryan N Contreras

Learn More
Japanese-cedar [Cryptomeria japonica (L.f.) D. Don] represents an alternative to leyland cypress [·Cuprocyparis leylandii (A.B. Jacks. & Dallim.) Farjon] as an evergreen screen or specimen plant for landscapes. It performs well under a range of soil and environmental conditions but has been underused attributable, in part, to unsightly winter browning(More)
Hibiscus acetosella Welw. ex Hiern. 'Panama Red' PP20,121 (Malvaceae) has generated public and grower interest due to its attractive red foliage and vigorous growth, however, a horticultural goal is to develop more compact forms. Even though organs of induced polyploids are often larger than the wild type, whole plants are often shorter in stature. Three(More)
Wide hybridization can lead to recombination of diverse traits and creation of unique phenotypes, but the resultant hybrids are often sterile as is the case with the intersubgeneric hybrid Rhododendron L. ÔFragrant AffinityÕ. Sterility in wide hybrids can either be genic or chromosomal; the latter may be overcome by induction of polyploidy, which can(More)
Interspecific hybridization in Tecoma Juss. was conducted to develop novel forms for the nursery industry. We report fertile hybrids from the cross T. garrocha Hieron. (pistillate parent) × T. stans (L.) Juss. ex Kunth. Leaf morphology of the F(1) hybrids of T. garrocha × T. stans was intermediate between the parents. GISH also confirmed hybridity. The(More)
SUMMARY. Ornamental grasses such as fountaingrass or napiergrass, collectively called pennisetums, belong to the genus Pennisetum, which is a diverse genus with over 80 species adapted to a wide range of climatic regions and known for its drought tolerance. Breeding efforts have led to improvements such as more intense purple foliage color, disease(More)
Japanese-cedar has been underused in landscapes of the United States until recent years. There are now over 100 cultivars, many of which are grown in the southeast of the United States. Performance of cultivars has been described from U.S. Department of Agriculture (USDA) Zone 6b to USDA Zone 7b; however, there are no reports on how cultivars perform in(More)
Considerable debates exist about the efficacy of foliar application of nutrients to Christmas trees, but little research has been conducted to determine whether this method of fertilization is beneficial. In this study, standard foliar and soil-applied fertilization products were applied to Nordmann fir Christmas trees under greenhouse and field-grown(More)
SUMMARY. New technologies such as online databases, interactive dichotomous keys, and online courses have changed the way some plant identification courses are delivered. These changing resources may create discrepancies between traditional instruction of landscape plant materials courses and the way modern students learn, which may result in students not(More)
Platycladus orientalis (L.) Franco (syn. Thuja orientalis L.), Thuja occidentalis L., and T. plicata D. Don. are conifers often used in the landscape. Most of the available cultivars of these species share the character of having foliage that turns an off-color during winter as a result of photoinhibition. Tetraploids of the related japanese-cedar(More)
There is a great deal of variation among japanese-cedar cultivars with regard to growth form, foliar characteristics, and winter browning. Differences in winter browning have been observed and documented by a number of authors. Previous research has established that there are differences in winter foliage color between cultivars included in the current(More)